IN 1948, BERNARD AND SOULIER described a young male patient with a severe bleeding disorder that was characterized by a prolonged bleeding time, thrombocytopenia, and extremely large platelets.1 They termed the disorder “la dystrophie thrombocytaire-hémorragipare congénitale.” Since then, an identical or similar disorder has been described in a large number of individuals, virtually always transmitted in an autosomal recessive manner and often occurring in persons whose parents are close relatives.

The first clue to the molecular abnormality affecting the platelets of patients with this disorder (now known as the Bernard-Soulier syndrome [BSS]) came in 1969 from the work of Gröttum and Solum,2 who noted reduced electrophoretic mobility of the platelets due to a marked decrease in the concentration of sialic acid on their membranes. Subsequently, Howard et al3 and Caen and Levy-Toledano4 found that the platelets of BSS patients failed to aggregate to ristocetin, a peptide antibiotic known to aggregate normal platelets but not the platelets of patients suffering from von Willebrand disease. Weiss et al5 in 1974 extended this observation by demonstrating a defect in the ability of BSS platelets to adhere to rabbit aortic subendothelium. They also suggested that the defect resulted from absence of a receptor for von Willebrand factor (vWF) on the platelet surface. Numerous other phenotypic abnormalities have been described in BSS, including defective platelet aggregation to bovine vWF,3,6abnormalities of membrane phospholipid content7,8 and coagulant activity,6,8 and morphological characteristics that include large size and disordered cytoskeletal structure.9,10 

The nature of the missing vWF receptor was suggested in 1975 when Nurden and Caen11 demonstrated that 1 of the 3 major carbohydrate-containing proteins on the platelet surface, glycoprotein I, was virtually absent in the platelets of BSS patients. The biochemical defect was defined further in the laboratories of Clemetson et al12 and Berndt et al,13 when they demonstrated, in unrelated patients with BSS, deficiencies of 4 polypeptides: glycoproteins (GP) Ibα, Ibβ, IX, and V. These polypeptides all associate on the platelet surface to form a receptor called the GP Ib-IX-V complex.

The importance of this receptor for normal hemostasis is perhaps best illustrated by the clinical history of the original patient described by Bernard and Soulier.14 As both a child and a young man, this patient suffered numerous bleeding problems, including prolonged bleeding after tooth extraction, life-threatening cerebrospinal hemorrhage, and orbital and periorbital hematomas after an accident. He died at 28 years of age of intracranial hemorrhage after a barroom brawl.

THE GP Ib-IX-V COMPLEX: STRUCTURE AND FUNCTION

The GP Ib-IX-V complex has two important roles in platelet function that explain the often severe bleeding observed in BSS: it mediates adhesion to the blood vessel wall at sites of injury by binding vWF and it facilitates the ability of thrombin at low concentrations to activate platelets.15 The interaction with vWF underlies another potentially important function that may be more relevant to thrombosis than to hemostasis: shear-induced platelet aggregation.16 Furthermore, the GP Ib-IX-V complex may have important roles in the process by which platelets are generated and possibly in platelet turnover, as evidenced by the decreased number and abnormal size of platelets from BSS patients.

The key structural features of the GP Ib-IX-V complex are depicted schematically in Fig 1. The complex comprises 4 distinct transmembrane polypeptide subunits, GP Ibα, GP Ibβ, GP IX, and GP V, with a stoichiometry based on monoclonal antibody binding of 2:2:2:1, respectively.17-20 Each of the 4 subunits is a member of the leucine-rich repeat motif superfamily, members of which are involved in such diverse processes as cell signaling, cell adhesion, and development.21,22 In the polypeptides of the GP Ib-IX-V complex, the leucine-rich repeat sequences are approximately 24 amino acids in length, occur singly or in tandem repeats, and are flanked by conserved N- and C-terminal disulfide loop structures.22 However, despite these structural similarities, the polypeptides comprising the GP Ib-IX-V complex all arise from distinct genes residing in different regions of the genome.23-27 

Fig. 1.

Schematic view of the platelet GP Ib-IX-V complex. Key structural features of the complex are shown. The leucine-rich repeats of the four polypeptides are drawn based on the structure determined for the porcine ribonuclease inhibitor, a protein made up entirely of leucine-rich repeats.32 The depicted polypeptide arrangement is based on the published stoichiometry determined by monoclonal antibody binding17-19 and on the associations determined for the polypeptides.47,112 A caveat about this depiction: the quantity of GP V on the platelet surface has only been determined using 2 GP V monoclonal antibodies,18,20 which could lead to overestimates or underestimates of true polypeptide number. In addition, no quantitation has ever been performed to indicate that every GP V molecule on the platelet surface is associated with the complex. Complexes of greater complexity having the same stoichiometry are also possible.22,82 Diamonds on stalks represent N-linked carbohydrates and circles on stalks represent O-linked carbohydrate.

Fig. 1.

Schematic view of the platelet GP Ib-IX-V complex. Key structural features of the complex are shown. The leucine-rich repeats of the four polypeptides are drawn based on the structure determined for the porcine ribonuclease inhibitor, a protein made up entirely of leucine-rich repeats.32 The depicted polypeptide arrangement is based on the published stoichiometry determined by monoclonal antibody binding17-19 and on the associations determined for the polypeptides.47,112 A caveat about this depiction: the quantity of GP V on the platelet surface has only been determined using 2 GP V monoclonal antibodies,18,20 which could lead to overestimates or underestimates of true polypeptide number. In addition, no quantitation has ever been performed to indicate that every GP V molecule on the platelet surface is associated with the complex. Complexes of greater complexity having the same stoichiometry are also possible.22,82 Diamonds on stalks represent N-linked carbohydrates and circles on stalks represent O-linked carbohydrate.

GP Ibα (135 kD, 610 amino acids) consists of an N-terminal globular domain28 that contains 7 tandem leucine-rich repeats and their flanking sequences, a 19-amino acid sequence rich in negatively charged aspartate and glutamate residues, and 3 sulfated tyrosines,29,30 a highly glycosylated, macroglycopeptide mucin core, a single transmembrane sequence, and a cytoplasmic tail of 96 amino acid residues.31 The structure of the leucine-rich repeats depicted in Fig 1 is based on the x-ray crystal structure of porcine ribonuclease inhibitor, a protein made up entirely of leucine-rich repeats.32 In this structure, each repeat forms a β-α structural unit (a short β-strand parallel to an α-helix), resulting in a horseshoe-shaped molecule in which the helices form the outer circumference and the β-strands form the inner surface. If the GP Ib-IX-V leucine-rich repeats adopt a similar structure, this produces a fan-shaped surface with most of the amino acid side chains exposed to solvent, a property that may maximize surface interactions with target proteins and that also has the effect of bringing the flanking sequences into proximity. The macroglycopeptide contains an O-linked, sialylated hexasaccharide on average every 3 to 4 amino acids,33-35creating a scaffold that extends the N-terminal globular domain and vWF binding site approximately 45 nm from the surface of the platelet plasma membrane.28 This region is highly polymorphic. In any individual, its length depends on which combination of 4 possible alleles is inherited. The products of these alleles differ in having 1, 2, 3, or 4 tandemly repeated copies of a 13-amino acid sequence,36,37 each of which has been predicted to add about 32 Å to the length of the macroglycopeptide.36 

GP Ibβ (25 kD, 181 amino acids) has a single leucine-rich repeat and is disulfide-linked to GP Ibα immediately proximal to the platelet plasma membrane.38 The cytoplasmic sequence of 34 amino acids contains a protein kinase A phosphorylation site at Ser16639 that appears to regulate platelet cytoskeletal rearrangement in response to agonist stimulation.40 

GP IX (22 kD, 160 amino acids), like GP Ibβ, has a single leucine-rich repeat motif41 and remains associated with GP Ib as a 1:1 complex when purified in Triton X-100.42 It has a short cytoplasmic tail of 5 amino acids. The cytoplasmic sequences of GP Ibβ and GP IX both have a membrane-proximal cysteinyl residue that can be palmitoylated in vitro, a modification that may provide additional anchorage for the complex in the platelet membrane.43 Analysis of guinea pig megakaryocyte proteins suggests that GP IX is primarily myristoylated rather than palmitoylated.44 

GP V (82 kD, 544 amino acids) has 15 leucine-rich repeats and a short cytoplasmic tail of 16 amino acids.45,46 It is thought to bridge adjacent GP Ib-IX complexes through an interaction with GP Ibα.47 The other feature of GP V is that it is one of a limited set of thrombin substrates on the platelet plasma membrane, with a major fragment, GP Vf1 (69.5 kD), released from the surface of thrombin-treated platelets.48 The functional significance of this cleavage in platelet physiology remains unclear.

The principal function of the GP Ib-IX-V complex in hemostasis is to initiate the arrest of platelets at sites of vascular injury. Like other adhesion receptors, ligation of the GP Ib-IX-V complex by vWF can transduce signals to the platelet cytoplasm, initiating the cascade of events that leads to the formation of a hemostatic platelet plug. However, unlike other adhesion receptors, the GP Ib-IX-V complex is a unique adhesive system unrelated in structure to members of the integrin, selectin, or Ig superfamilies, which mediate other aspects of blood cell–vessel wall interaction.49 The binding site for the GP Ib-IX-V complex resides within the A1 domain of vWF,50,51 included within residues 480-718 of the mature sequence.52 Mature vWF has a subunit molecular weight of 230,000 (2,050 amino acids)53 and circulates in a nonadhesive form consisting of disulfide-linked multimers of up to 20 × 106 in molecular weight.54 vWF bound to the subendothelial matrix is believed to undergo a conformational change that reveals a normally cryptic binding site for the GP Ib-IX-V complex within its A1 domain.55 vWF also binds to the GP Ib-IX-V complex under the influence of high shear forces16by induction of conformational changes in either the receptor or vWF or in both.56,57 Consistent with this finding, gain-of-function mutations occur in both the receptor and in vWF that enhance the receptor-ligand interaction. In platelet-type (or pseudo) von Willebrand disease, mutations of GP Ibα (Met239→Val58 or Gly233→Val59) result in a receptor complex with higher affinity for circulating vWF.60,61 In type 2B von Willebrand disease, point mutations in the vWF A1 domain clustered around the Cys509-Cys695 disulfide bond and between Met540 and Arg578 yield a form of vWF with enhanced avidity for the native GP Ib-IX-V receptor on platelets.62 A number of modulators have been identified that also enhance the interaction between vWF and the GP Ib-IX-V complex.63 These include the antibiotic ristocetin, from the gram-negative bacterium Nocardia lurida, which appears to function, at least in part, by binding to proline-rich sequences flanking the disulfide bond between Cys509 and Cys695 in the vWF A1 domain.64-66 A second modulator, botrocetin (a disulfide-linked heterodimer of 28 kD from the venom of the South American pit viper, Botrops jararaca) activates vWF adhesive function towards platelets by binding to noncontiguous sequences within the A1 domain loop.66,67 

The regions involved in the binding of vWF to GP Ibα have only been partially defined and appear to be dependent, in part, on conformational structure in both the ligand and receptor. In vWF, both the peptide sequence, Asp514 to Glu542,66 and the region encompassing Glu596 and Lys59968 have been proposed as receptor recognition sites. In GP Ibα, the vWF binding site is located within the N-terminal approximately 300 amino acids.30,69,70 Three regions within this domain appear to be important for vWF binding (Fig 2). One corresponds to the anionic sulfated-tyrosine sequence,29,30,71,72 which appears to be preferentially involved in botrocetin-dependent binding of vWF.30,71Sulfation of tyrosine residues in this sequence is more critical for botrocetin-dependent than for ristocetin-dependent binding of vWF,72 but both modulators require the modification for optimum effect. An Escherichia coli-produced GP Ibα fragment containing the sequence encompassing Gln221-Leu318 has been reported to contain the ristocetin-dependent binding site for vWF, with a disulfide-bond between Cys248 and Cys264 critical for function.73 Because Cys248 and Cys264 are normally disulfide-bonded to Cys209 and Cys211, respectively,74 the significance of this finding is not clear. The leucine-rich repeats also appear to have an important role in vWF binding, as suggested by studies of BSS patients who express mutant GP Ib-IX-V complexes on their platelets. Platelets expressing these mutant complexes, which both result from mutations in the GP Ibα leucine-rich repeats (Leu47→Phe75 and Ala156→Val76), bound vWF less efficiently than did normal platelets. Finally, two gain-of-function mutations (Gly 233→Val59 and Met 239→Val58) in platelet-type von Willebrand disease are located in the flanking sequence C-terminal to the leucine-rich repeats.22 Both of these mutants spontaneously bind vWF in the absence of ristocetin, botrocetin, or shear, implying that this domain may be directly involved in vWF binding or could regulate that function.

Fig. 2.

The GP Ibα N-terminus with the regions shown to be important for vWF binding. Asterisks indicate that the tyrosines are sulfated.

Fig. 2.

The GP Ibα N-terminus with the regions shown to be important for vWF binding. Asterisks indicate that the tyrosines are sulfated.

Available evidence indicates that the GP Ib-IX-V–vWF interaction may in many ways be similar to the interaction between selectins and their ligands. Similar to the rolling of leukocytes mediated by selectins, recent observations indicate that the GP Ib-IX-V complex can mediate translocation of platelets along a surface coated with vWF. Such a phenomenon requires that the bonds be able to form and break rapidly. In the studies of Savage et al,77 the vWF–GP Ib-IX-V interaction could slow the platelets in this way, but a further interaction between vWF and the GP IIb-IIIa complex was required to fully arrest the platelets. As yet, it is unclear how this in vitro phenomenon relates to the situation in vivo, because vWF in the environment of the subendothelium may adapt a different conformation than when immobilized on glass. The influence of vWF conformation on platelet translocation was nicely demonstrated in the studies of Moroi et al78 (in a system similar to that of Savage et al77), who demonstrated that addition of botrocetin to vWF immobilized on glass markedly decreased platelet translocation, presumably because it increased the affinity of the interaction.

Thrombin also binds within the N-terminal sequence, His1-Glu282, of GP Ibα, specifically to the anionic sulfated-tyrosine sequence.30,79 Thrombin recognition, in contrast to the binding of vWF, has a greater stringency requirement for tyrosine sulfation in that all 3 tyrosine residues must be sulfated for effective binding of thrombin to GP Ibα.72 High-affinity binding to the GP Ib-IX-V complex may also involve recognition of segments of the leucine-rich repeat C-terminal flanking sequence80,81 and GP V.82 Although the agonist action of thrombin towards platelets primarily involves signaling through the 7-transmembrane PAR-1 and/or PAR-3 thrombin receptors,83,84 binding of thrombin to the GP Ib-IX-V complex facilitates the platelet response to low concentrations of thrombin.85-87 A defective response to thrombin undoubtedly contributes to the bleeding diathesis of patients with BSS. A detailed discussion of the nuances of thrombin's association with the GP Ib-IX-V complex is beyond the scope of this review. The interested reader is referred to the recent review of Jamieson.88 

Although it is unknown how thrombin signals through the GP Ib-IX-V complex, there is increasing evidence that ligation of vWF initiates signaling events that result ultimately in inside-out activation of the integrin, GP IIb-IIIa, and platelet aggregation.16,89Signaling by other adhesion receptors can be initiated by receptor cross-linking90; recent evidence suggests that a similar mechanism may be operative in GP Ib-IX-V–dependent signaling in platelets. First, a monomeric 39/34-kD proteolytic fragment of vWF is able to bind to the GP Ib-IX-V complex and inhibit binding of multimeric native vWF, but does not activate platelets.52Second, GP Ibα is arranged on the cell surface as part of a larger receptor complex, with two or more GP Ibα subunits forming a cluster with the other glycoproteins of the complex.22 Third, GP Ibα is associated via its cytoplasmic region with actin-binding protein and 14-3-3ζ protein (see below and Fig 1), both of which form noncovalent dimers. Finally, the 50-kD (presumably bivalent) viper venom protein, alboaggregin, binds to GP Ibα and activates platelets, whereas structurally related monomeric 25-kD venom proteins bind to the same domain on GP Ibα, but do not activate platelets.91 

The signaling events induced by vWF binding to GP Ib-IX-V in the presence of shear, ristocetin, or botrocetin include elevation of cytosolic Ca2+ and activation of protein kinases.92-95 Ser/Thr protein kinases become activated, as 2 of their substrates, pleckstrin and the myosin light chain, are rapidly phosphorylated.92 Two major tyrosine kinase substrates (∼76 and ∼36 kD) also become phosphorylated,92 but the identity of neither is known.95 Interestingly, both species are also phosphorylated in response to 50-kD alboaggregin.91 Other consequences of vWF binding to GP Ib-IX-V include association of activated phosphatidylinositol 3-kinase (PI 3-kinase) and src with the cytoskeleton,94 breakdown of phosphatidylinositol 4,5-bisphosphate, generation of phosphatidic acid, activation of phospholipase A2, and synthesis of arachidonic acid and thromboxane A2.92 

One of the interesting features of the GP Ib-IX-V complex is that none of the cytoplasmic sequences of its 4 constituent polypeptides contains motifs known to interact with signaling proteins. Nevertheless, these regions do interact with proteins of the platelet membrane cytoskeleton, providing a potential means for the complex to transduce activation signals. The cytoplasmic domain of GP Ibα contains a binding site for actin-binding protein within the sequence Thr536 to Leu554.96 This association with actin-binding protein links the complex with a network of short submembranous actin filaments.97,98 This membrane skeleton of quiescent platelets contains other cytoskeletal proteins, including spectrin, dystrophin, talin, vinculin, and protein 4.1, and several signaling proteins, including the tyrosine kinases src, yes, and syk, the small G protein, p21 ras, and the tyrosine phosphatase, SHP 1.99-101 In unstimulated platelets, much of the GP IIb-IIIa complex is also attached to the membrane skeleton,99suggesting that one of the functions of this structure may be to preassemble key signaling elements, allowing transmission of signals after GP Ib-IX-V ligation, eventually leading to GP IIb-IIIa activation. Consistent with a role for cytoskeletal attachment in GP Ib-IX-V functions, recent studies show that even small C-terminal truncations of GP Ibα greatly increase the mobility of the complex within the plane of the plasma membrane and decrease its ability to bind vWF.102 

A second possible mechanism by which the GP Ib-IX-V complex may transmit signals derives from the recent finding that its cytoplasmic domain contains binding sites for the ζ isoform of 14-3-3.103,104 Although platelet 14-3-3ζ was originally reported to have phospholipase A2 activity,105 this enzymatic activity was not found in other studies.106Rather, 14-3-3 proteins have recently been shown to regulate the activity and assembly of key signaling molecules that, in turn, regulate such diverse processes as mitogenesis, cell cycling, vesicular transport, and apoptosis. Proteins reported to bind 14-3-3 include the cell death agonist BAD, raf-1, bcr, cbl, PKCε, PKCγ, the cdc25a and cdc25b phosphatases, the p85 subunit of PI 3-kinase, tyrosine hydroxylase, tryptophan hydroxylase, and ADP ribosyltransferase.107-109 The 14-3-3 protein family consists of a number of closely related isoforms with subunit molecular weights of approximately 30 kD that form highly stable homodimers and heterodimers.107 This latter property allows them to bridge and assemble cytoplasmic proteins containing 14-3-3 recognition motifs. The 14-3-3 isoform most commonly identified as binding signaling molecules is 14-3-3ζ.107 

Recent analysis of 14-3-3 binding to raf-1 has identified 2 nonoverlapping binding sites for 14-3-3 within raf-1.108Both sites contain serines within a conserved R S X S X P motif, a motif also found in other 14-3-3 binding proteins, including PKCε, cdc25b, bcr, and BAD. The binding of 14-3-3 to these sites is regulated by phosphorylation, with the presence of phosphate on the serine favoring binding. Within the GP Ib-IX-V complex, a major binding site for 14-3-3ζ corresponds to the 4 C-terminal amino acids of GP Ibα, Gly-His-Ser-Leu.104,110 Additional binding sites have been identified by analysis of overlapping peptides corresponding to the cytoplasmic sequences of GP Ibα, GP Ibβ, GP IX, and GP V.110 These include the central region of the GP Ibα cytoplasmic domain (Arg557-Gly575) and the entire cytoplasmic tail of GP V. Another binding site for 14-3-3ζ encompasses the PKA phosphorylation site in GP Ibβ. Serine phosphorylation of a synthetic peptide containing this sequence increased its affinity for 14-3-3ζ. This effect of phosphorylation on a 14-3-3ζ–binding sequence in GP Ibβ suggests an additional effect of PKA-dependent phosphorylation on regulating platelet activation. Because GP Ibβ phosphorylation specifically inhibits actin polymerization,40 the increased affinity for 14-3-3ζ is consistent with a role for this protein in the control of this process. Whether 14-3-3ζ is involved in mediating the assembly of signaling complexes in response to vWF ligation of the GP Ib-IX-V complex remains to be determined.

SYNTHESIS OF THE GP Ib-IX-V COMPLEX

GP Ibα, Ibβ, and IX exist in equal numbers on the surfaces of platelets17 and cells transfected with the cDNAs encoding the 3 polypeptides.111 Only half as many molecules of GP V are found on platelets,18,19 although the preciseness of this molar relationship with the rest of the complex requires further characterization. Based on studies using both transfected cells47,111-113 and the platelets of BSS patients with different mutations,114-116 it appears that maintenance of this stoichiometry relies primarily on the relative instability of partial complexes and single polypeptides. For example, in studies of GP Ibα surface expression in transfected cells, it was shown that this polypeptide is expressed on the surface of the cells most efficiently when both GP Ibβ and GP IX were cotransfected.111 Cotransfection with GP Ibα of less than the full complement of the other 2 polypeptides did not completely prevent GP Ibα expression, but did decrease it substantially. None of these 3 polypeptides is expressed efficiently on the cell surface unless expression in the cells is increased by manipulations such as gene amplification.112,117 Combinations of 2 polypeptides are more efficient in reaching the cell surface than single polypeptides if the 2 polypeptides interact with each other directly.112 GP V is not necessary for efficient expression of the rest of the complex and has only a minor effect, at most, on the expression of GP Ib-IX.47,118,119 It is the only 1 of the 4 complex polypeptides that can be efficiently expressed alone on the surfaces of transfected cells, although its surface expression is increased in the presence of the rest of the complex.47 From these studies, it was suggested that BSS could be caused by mutations of either GP Ibα, GP Ibβ, or GP IX, but the typical syndrome was unlikely to be caused by mutations of GP V.47,111,112 

The molecular defects characterized thus far in patients with BSS support the findings from these in vitro studies in that mutations responsible for BSS have only been shown to involve the genes for GP Ibα, GP Ibβ, and GP IX (Table1). Mutations of the latter 2 polypeptides apparently cause the disorder by decreasing surface expression of GP Ibα.114,115,121 In several of the cases described, residual quantities of the unaffected polypeptides are still found in the platelets.114,116,122 

Table 1.

Clinical Profiles of BSS Patients

Case No. Year-150Platelet Count-151Clinical Description Genetic Defect Ref.
1  1948  15-45 French male. BSS index case. Presented at age 15 days with epistaxis and anal hemorrhage, then frequent bruising, GI bleeding. Later bleeding from trauma, including bilateral scrotal hematoma and severe epistaxis. BT >20 min. Died of cerebral hemorrhage at 28. Sister died at 31 mo of prolonged bleeding. Parents, other siblings unaffected.  Unknown  1, 160  
2  1974  75-280 African-American male. Recurrent mucosal bleeding, giant platelets, BT >20 min. Female first cousin also BSS, with excessive menstrual and postpartum hemorrhage. In both cases, bleeding responded to platelet transfusions.  GP Ibα, homo. CTC → CCC, Leu129 → Pro.  5, 200  
3  1976  110  French female. Severe hemorrhage during pregnancy; 3 successive miscarriages. Giant platelets, BT >20 min, no RIPA.  Unknown  160  
1976   80  Greek female. Epistaxis, menorrhagia, and severe hemorrhage after teeth extractions. Giant platelets, BT >20 min, no RIPA.  Unknown  160  
5  1979   French male. Long BT, large platelets, lack of platelet aggregation to ristocetin or bovine vWf.  Unknown  203  
6  1980   Female. Giant platelets and absent RIPA. BT >12 min.  Unknown  204  
1981   66  Caucasian female. Considered normal until severe bleeding from minor scalp laceration at age 1. Severe GI hemorrhage at age 4. Easy bruising and frequent epistaxis. Required transfusion on menarche at age 11, menstrual bleeding controlled by OCP. Vaginal delivery supported by platelet transfusions. BT >20 min. Brother also BSS, required transfusion following circumcision. Easy bruising, gingival bleeding, and severe epistaxis requiring transfusions approximately every 3 mo as a child. BT >20 min. Iron deficient. Sister unaffected. Parents (third cousins) are of German ancestry with no or minor bleeding.  GP Ibα, homo. Dinucleotide deletion (TAT) at Tyr492; Silent A → G at Arg342; T → C at −5 of 5′ UTR.  120, 205  
8  1981  50  Kuwaiti female. Bleeding from gums, palate at 2 mo, regular transfusions throughout childhood. Severe prolonged bleeding at age 6 (tooth extractions) and age 13 (menarche, controlled by OCP). Major problem was constant gingival oozing. BT >20 min. Sister had epistaxis at age 3 and transfusions at age 6 (tooth extractions) and age 14 (menarche). Symptoms milder than proband, despite platelet count of 20,000/μL and BT >20 min. Eight other siblings and parents (first cousins) are normal.  Unknown  3, 205 
9  1982  39-72  Swiss female. Bleeding episodes and absent RIPA, normal response to other agonists. Giant platelets, BT = 8 min. Unknown  12  
10  1982   French female. Thrombocytopenia, giant platelets. BT >30 min, platelet count normal following splenectomy. Absent RIPA.  Unknown  12  
11  1982  French male. Thrombocytopenia, BT >30 min. Platelets slightly larger than normal. No RIPA at low ristocetin concentration, ∼20% normal response at 1.4-3 mg/mL.  Unknown  12  
12  1983 70-90  Caucasian female. Life-long history of bruising, epistaxis and profuse bleeding. Severe menorrhagia until started on OCP. Giant platelets, lack of ristocetin- and bovine vWF-dependent aggregation. Brother also BSS, parents (first cousins) are normal. Unknown  13  
13  1983  70-90  Caucasian female. Life-long history of bruising, epistaxis and profuse bleeding. Mentally retarded, thrombocytopenia, ∼7% of normal GP Ib level.  Unknown 13  
14  1984  30-60  French-Canadian family. Severe epistaxis, hemorrhage after dental surgery. BSS in 4 brothers and 3 sisters, the latter also menorrhagic. One sister experienced prolonged hemorrhage after cone biopsy of cervix. Increased BT, giant platelets, no RIPA.  Unknown  206, 207  
15  1985  60-100 Afrikaner female. Spontaneous tonsillar hemorrhage at age 5, frequent epistaxis, prolonged bleeding after tooth extractions. Excessive menstrual bleeding controlled by OCP. Gross morphological platelet abnormalities, many “bizarre and giant forms.” Sister and two brothers also with BSS, two other brothers normal. Mother's family “bleeders.” Sister had near-fatal bleeding during childbirth. Affected siblings required lifelong transfusions; in adulthood, only following surgical procedures or severe trauma. Splenectomy in proband and two siblings appeared to reduce the number of severe bleeding episodes.  Unknown  158 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
16  1985  120 Afrikaner female. History of excessive and prolonged bleeding from childhood following minor injury. Marked menorrhagia. Transfusions required for tooth extractions, surgical procedures, after dilation and curettage and a thyroidectomy at age 21.  Unknown  158  
17 1986   81  Male. Bolzano variant. Life-long history of epistaxis and gingival bleeding. Bleeding episodes continued after splenectomy at age 9 for thrombocytopenia. BT = 9 min. Sister died at age 2 from intracranial bleeding. Patient also homozygous for Thr145 → Met Koa polymorphism. Parents normal.  GP Ibα, homo. GCT → GTT, Ala156 → Val.  76, 208  
18 1986   62  Male. History of easy bruising, ecchymoses, and profuse bleeding from cuts. Mother bruises easily, father asymptomatic.  Unknown  208  
19  1987  38-67 Male. History of subcutaneous hematomas following injury. Prolonged bleeding after appendectomy. BT >15 min. Large platelets, no RIPA. Brother also BSS. No family history of bleeding.  Unknown  209 
20  1987  100  Swiss female. Suffered from epistaxis, gingival bleeding, ecchymoses, frequent menorrhagia. Splenectomy and steroid treatment for suspected ITP ineffective. Giant platelets and no RIPA. Six other family members heterozygous for BSS. Unknown  167  
21  1988  10-30  French-Canadian brother and sister with BSS, parents and other sister are normal. Unknown  206  
22  1988  25-100  Male. Life-long history of easy bruising, recurrent epistaxis and occasional petechiae. Giant platelets, no aggregation to ristocetin or bovine vWF. Presented at age 14 with thrombocytopenia and bleeding following tooth extraction; required blood and platelet transfusions. Initially diagnosed as ITP; ineffective prednisolone treatment. At age 18, elective splenectomy lessened severity of subsequent epistaxis. DDAVP apparently shortened bleeding time.  Unknown  168  
23  1988 25-30  Caucasian female. Life-long history of easy bruising, frequent epistaxis, occasional gum bleeding, and menorrhagia. Prolonged bleeding after dental extractions. Large platelets, BT >20 min. Refractory to platelets from random donors. Developed three red cell alloantibodies secondary to transfusions. OCP controlled menorrhagia and resulted in “less bruising and less frequent epistaxes.” DDAVP treatment was apparently ineffective. Sister also with BSS. Unknown  159  
24  1989   28  Caucasian female. Multiple blood or platelet transfusions after trauma or surgery. Abnormal RIPA, giant platelets. Hospitalized at 32 wk gestation, pelvic ultrasound showed fetal ascites and pericardial effusion. Isoimmunity suppressed by steroids and i.v. gamma globulin. Plasmapheresis allowed additional platelet transfusion. Gingival bleeding and ecchymotic suprapubic amniocentesis site. Amniocentesis led to premature membrane rupture. Chorioamnionitis 3 days later resulted in spontaneous labor (platelet count 8,000/μL). Excessive vaginal bleeding 3 wk after caesarean delivery; hysterectomy. Brother also with BSS. Parents second cousins.  Unknown  161  
25 1989  7-138  Male. Life-long abnormal bleeding, prolonged gingival bleeding. Uncomplicated cesarean birth and circumcision. Thrombocytopenia (45,000/μL) at age 14 mo, BT >21 min. Splenectomy at age 3. Recurrent childhood epistaxis and ecchymoses, excused from physical education. Bleeding symptoms decreased at puberty, bled from tooth extractions at age 23. Worked as meatcutter from age 20 without major bleeding episodes. At age 30, painless upper GI bleeding required transfusions, as did facial lacerations following car accident. Brother, sister, and two children normal; no family history of bleeding.  Unknown  210  
26  1990   Female. Excessive bleeding after tonsillectomy, menorrhagia, epistaxis and profuse bleeding associated with ear piercing. Younger brother also BSS with frequent epistaxis, once requiring hospitalization. Parents, two other siblings and five children normal.  Unknown. Probably not GP Ibα defect based on RFLP.  211  
27  1990   25 Spanish male. Life-long mucocutaneous bleeding, BT >30 min. Thrombocytopenia progressively worse from 120,000/μL in 1976. Splenectomy at age 6. Other family members normal.  GP Ibα, homo. TGC → AGC, Cys209 → Ser.  199, 212 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
28  1990  32  Male. Life-long bleeding tendency, frequent spontaneous epistaxes and mucosal hemorrhages requiring transfusions. Giant platelets with prominent granulations.  GP Ibα, hetero. TGG → TGA, Trp343 → stop in one allele, other defect unknown. 198  
29  1990   48  Danish female. Frequent epistaxes, ∼30% normal level of GP Ibα. BT = 11 min. No RIPA. Sisters aged 19 and 9 also BSS, BTs of 12 and 13 min, respectively. One sister bled profusely following dental extractions.  Unknown 213  
30  1990   32  Danish female. Microscopic hematuria, ∼7% normal level of GP Ibα. BT = 20 min (7 min at original diagnosis). No RIPA. Sister aged 71 also BSS, BT = 7 min. Consanguineous parents.  Unknown  213  
31  1990  47  Danish female. Severe bleeding at delivery, GP Ibα ∼22% normal level. BT = 11.5 min, no RIPA.  Unknown 213  
32  1990   64  Danish male. Numerous episodes of GI bleeding, ∼16% normal level of GP Ibα. BT = 8.5 min, no RIPA.  Unknown  213  
33  1991   51 Swedish female. Mild hypothyroidism and, since age 6, insulin-dependent diabetes mellitus. At 30 mo, subcutaneous hematoma on forehead, incision resulted in week-long bleeding. Frequent epistaxes and profuse menstrual bleeding. At age 20, repeated blood transfusions for bleeding associated with IUD use. At age 32, anemia. Giant platelets, absent RIPA. BT >20 min, some response to DDAVP. Father and three brothers normal, mother with menorrhagia.  Unknown  171 
34  1991  10-65  Swedish male, Karlstad variant. Thrombocytopenia from early childhood, life-long bleeding symptoms, severe gastric hemorrhage, subcutaneous hematomas, epistaxes and easy bruising. Bilateral subdural hematomas following violent sneeze. Giant platelets, no RIPA, low GP Ibα by flow cytometry. Corticosteroid treatment for ITP was ineffective and was discontinued. Splenectomy resulted in increased platelet count from 40,000 to 65,000/μL. BT >20 min, some beneficial effect of DDAVP. Normal number of megakaryocytes in bone marrow. Mother died of puerperal hemorrhage at childbirth. Parents with common ancestry from late seventeenth century. GP Ibα, homo. TGG → TGA, Trp498 → stop.  122, 171 
35  1992   80  Caucasian male. Frequent epistaxes, once resulting in hospitalization. Diagnosed prior to dental extraction because of thrombocytopenia. Mother had long history of bleeding, including bleeding associated with tonsillectomy, epistaxes, severe menorrhagia requiring hysterectomy, and GI bleeding. Autosomal dominant.  GP Ibα, hetero. CTC → TTC, Leu57 → Phe.  75 
36  1993   Female. Life-long bleeding tendency, frequent episodes of mucosal bleeding, particularly melena. Two siblings affected, one sister unaffected. Giant platelets, no RIPA, membrane GP Ib deficient by immunostaining.  GP IX, compound hetero. GAC → GGC, Asp21 → Gly; AAC → AGC, Asn45 → Ser.  114 
37  1993   Japanese female. General anaesthesia induced by fentanyl and diazepam, and maintained with nitrous oxide, fentanyl and 0.5% enflurane without exacerbating the bleeding tendency.  Unknown 173  
38  1994   24  Japanese female. Diagnosed BSS by giant platelets, no RIPA, thrombocytopenia and GP Ib deficiency. BT = 15 min. Parents normal, elder sister also with BSS. Parents consanguineous.  GP Ibα, homo. TCA → TAA, Ser444 → stop. 197  
39  1994  30-60  Caucasian male. Life-long bleeding tendency and epistaxes. Giant platelets, no RIPA and increased BT. Mother had mild bleeding, father and sister normal, brother with mild thrombocytopenia but no bleeding.  GP IX, homo. AAC → AGC, Asn45 → Ser.  214  
40  1994  35  Caucasian male. Severe life-long bleeding, mainly epistaxes and hematomas requiring multiple blood transfusions. Giant platelets, BT >20 min. Splenectomy at age 4 decreased bleeding tendency and obviated transfusions, but severe epistaxis returned at age 37 associated with physical exertion. Controlled by intranasal tranexamic acid.  GP Ibα, homo. Deletion of T in codon 76, frame shift and truncation after 19 residues.  172  
41  1994  75  Japanese female. Spontaneous epistaxes from early childhood, menorrhagia. ITP diagnosed at age 16, ineffective corticosteroid therapy and splenectomy. Giant platelets, no RIPA, GP Ib deficient by SDS-PAGE. Brother has mild thrombocytopenia, but no bleeding. Parents consanguineous.  GP IX, homo. TGG → TGA, Trp126 → stop.  116, 215 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
42  1994  58  Male. Thrombocytopenia and prolonged BT not corrected by DDAVP or tranexamic acid. History of mild purpura and an episode of prolonged gingival bleeding following a blow to the mouth at age 2. Steroid treatment ineffective. Brother diagnosed as ITP at age 4 after severe hematemesis, intermittent petechiae. Both brothers no RIPA, BT >15 min. Parents normal.  Unknown  169  
43  1994  65  Female. Petechiae, giant platelets, no RIPA. BT >45 min, decreased to 6.5 min for 4-5 h after i.v. DDAVP. Sister also BSS, platelet count 45,000/μL, BT = 18 min (5 min after DDAVP).  Unknown  174  
44  1995  100-150  Male. Nancy I variant. Life-long bleeding, bruising and epistaxes requiring platelet and erythrocyte transfusions, BT >10 min. Giant platelets and no RIPA. Brother and sister also affected. Parents and other brother normal.  GP Ibα, homo. CTC (Leu179) deleted.  216 
45  1995   42  Japanese female. Severe menorrhagia and life-long bleeding. Initially diagnosed as ITP, ineffective corticosteroid therapy and splenectomy. Diagnosed as BSS at age 26 by low platelet count, giant platelets, no RIPA and GP Ib deficiency. At ages 27 and 29, vaginal childbirth accompanied by platelet transfusions. Parents consanguineous.  GP Ibα, homo. One base deletion in AAAAAAA sequence, 58-residue frame shift and premature stop.  116  
46  1995   83  Male. Velo-cardio-facial syndrome with neonatal mild congestive heart failure due to conoventricular septal defect, thrombocytopenia. Abnormal bleeding from cardiac catheterization (18 mo) and circumcision (age 3), recurrent otitis media, delayed speech. Large platelets, diminished RIPA, epistaxis. Markedly low GP Ibα by flow cytometry.  GP Ibβ, compound hetero. C → G mutation at −133 (GATA site), other β allele deleted.  182  
47  1995   Male. Diagnosed at age 7 with severe mucocutaneous hemorrhage. Low platelet count, giant platelets and reduced prothrombin consumption. History of repeated epistaxes and severe post-traumatic hemorrhage. Many platelet transfusions led to anti-HLA and anti-GP Ib alloimmunization and hepatitis B and C infection. Hospitalized due to severe anemia and intermittent melena. Upper endoscopy revealed esophagogastric ecchymoses, angiodysplasia of the duodenum, and vascular ectasias and purpuric ecchymoses of cecum and colon.  Unknown  217  
48 1996   Japanese female. Bleeding tendency since childhood, menorrhagia. Found to be thrombocytopenic at second pregnancy (age 27), no RIPA, giant platelets. Childbirth accompanied by platelet transfusion. Sister also BSS. Parents first cousins.  GP IX, homo. TGT → TAT, Cys73 → Tyr.  121  
49  1996  Japanese male. Life-long bleeding, episodes of severe spontaneous epistaxes. Diagnosed as ITP (aged 9), prednisolone without effect. At age 23, bled in lungs and diagnosed BSS. Giant platelets, no RIPA, low GP Ib levels. Father also BSS, paternal aunt died of blood loss, aged 7. Parents and paternal grandparents consanguineous. GP IX, homo. TGT → TAT, Cys73 → Tyr.  121  
50 1996  30-50  Caucasian male. Bleeding disorder from early childhood, bled from tonsillectomy. Near-fatal bleeding as adult from splenectomy for suspected ITP. Recurrent bruising and severe GI bleeding often requiring hospitalization and blood or platelet transfusion. Treated with ε-aminocaproic acid. BT >20 min. Mother, sister, daughter normal. Parents consanguineous.  GP Ibα, homo. AAG → AGA, Lys19 → Arg due to A deletion, frame shift, stop at codon 21.  170  
51  1997  183-246  Japanese female. Variant form of BSS. Frequent spontaneous epistaxes during childhood. Later, bleeding tendency diminished and no epistaxes or menorrhagia. Giant platelets, BT = 9.5 min, no RIPA or botocetin-induced aggregation in PRP. Both near normal with washed platelets. Diagnosed with type 2A vWD. GP Ibβ not disulfide linked to GP Ibα. Younger sister clinically similar. Parents with no bleeding history. Mother's platelets moderately enlarged, father's normal.  GP Ibβ, compound hetero. TAC → TGC, Tyr88 → Cys; GCC → CCC, Ala108 → Pro.  183  
52  1997   60  Japanese female. History of bleeding, recurrent epistaxes, and melena from early childhood. Giant platelets, no RIPA, BT >15 min. Parents consanguineous. No family history of bleeding.  GP Ibα, homo. TG deletion at 972-975 of gene, frame shift after Thr294, premature stop. 218  
53  1997   25  Japanese male. History of recurrent epistaxes and melena from early childhood. Giant platelets, BT >15 min. Parents consanguineous. No family history of bleeding, but father had low platelet count.  GP Ibα. compound hetero. T insertion at 1418; A deletion in AAAAAAA (1438-44), truncation. Both lead to premature termination.  218 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
54  1997  50-75 Male. Life-long bleeding tendency, spontaneous epistaxes up to age 20, then decreased. Splenectomy at age 24. After age 35, gingival bleeding with variable frequency and severity. Melena over 6 wk period at age 43 required hospitalization, but not transfusions. Giant platelets, no RIPA, BT = 4.5-6 min. Parents (first cousins) with no bleeding history.  GP IX, homo. TTT → TCT Phe55 → Ser in leucine-rich repeat.  219  
55  1997  20-30  Caucasian male. Mother and paternal grandfather of German descent. Large platelets and profuse bleeding tendency requiring frequent transfusions. No RIPA. BT >15 min. Large amounts of glycocalicin in plasma. Brother and sister were normal.  Same as case 7. 176 
Case No. Year-150Platelet Count-151Clinical Description Genetic Defect Ref.
1  1948  15-45 French male. BSS index case. Presented at age 15 days with epistaxis and anal hemorrhage, then frequent bruising, GI bleeding. Later bleeding from trauma, including bilateral scrotal hematoma and severe epistaxis. BT >20 min. Died of cerebral hemorrhage at 28. Sister died at 31 mo of prolonged bleeding. Parents, other siblings unaffected.  Unknown  1, 160  
2  1974  75-280 African-American male. Recurrent mucosal bleeding, giant platelets, BT >20 min. Female first cousin also BSS, with excessive menstrual and postpartum hemorrhage. In both cases, bleeding responded to platelet transfusions.  GP Ibα, homo. CTC → CCC, Leu129 → Pro.  5, 200  
3  1976  110  French female. Severe hemorrhage during pregnancy; 3 successive miscarriages. Giant platelets, BT >20 min, no RIPA.  Unknown  160  
1976   80  Greek female. Epistaxis, menorrhagia, and severe hemorrhage after teeth extractions. Giant platelets, BT >20 min, no RIPA.  Unknown  160  
5  1979   French male. Long BT, large platelets, lack of platelet aggregation to ristocetin or bovine vWf.  Unknown  203  
6  1980   Female. Giant platelets and absent RIPA. BT >12 min.  Unknown  204  
1981   66  Caucasian female. Considered normal until severe bleeding from minor scalp laceration at age 1. Severe GI hemorrhage at age 4. Easy bruising and frequent epistaxis. Required transfusion on menarche at age 11, menstrual bleeding controlled by OCP. Vaginal delivery supported by platelet transfusions. BT >20 min. Brother also BSS, required transfusion following circumcision. Easy bruising, gingival bleeding, and severe epistaxis requiring transfusions approximately every 3 mo as a child. BT >20 min. Iron deficient. Sister unaffected. Parents (third cousins) are of German ancestry with no or minor bleeding.  GP Ibα, homo. Dinucleotide deletion (TAT) at Tyr492; Silent A → G at Arg342; T → C at −5 of 5′ UTR.  120, 205  
8  1981  50  Kuwaiti female. Bleeding from gums, palate at 2 mo, regular transfusions throughout childhood. Severe prolonged bleeding at age 6 (tooth extractions) and age 13 (menarche, controlled by OCP). Major problem was constant gingival oozing. BT >20 min. Sister had epistaxis at age 3 and transfusions at age 6 (tooth extractions) and age 14 (menarche). Symptoms milder than proband, despite platelet count of 20,000/μL and BT >20 min. Eight other siblings and parents (first cousins) are normal.  Unknown  3, 205 
9  1982  39-72  Swiss female. Bleeding episodes and absent RIPA, normal response to other agonists. Giant platelets, BT = 8 min. Unknown  12  
10  1982   French female. Thrombocytopenia, giant platelets. BT >30 min, platelet count normal following splenectomy. Absent RIPA.  Unknown  12  
11  1982  French male. Thrombocytopenia, BT >30 min. Platelets slightly larger than normal. No RIPA at low ristocetin concentration, ∼20% normal response at 1.4-3 mg/mL.  Unknown  12  
12  1983 70-90  Caucasian female. Life-long history of bruising, epistaxis and profuse bleeding. Severe menorrhagia until started on OCP. Giant platelets, lack of ristocetin- and bovine vWF-dependent aggregation. Brother also BSS, parents (first cousins) are normal. Unknown  13  
13  1983  70-90  Caucasian female. Life-long history of bruising, epistaxis and profuse bleeding. Mentally retarded, thrombocytopenia, ∼7% of normal GP Ib level.  Unknown 13  
14  1984  30-60  French-Canadian family. Severe epistaxis, hemorrhage after dental surgery. BSS in 4 brothers and 3 sisters, the latter also menorrhagic. One sister experienced prolonged hemorrhage after cone biopsy of cervix. Increased BT, giant platelets, no RIPA.  Unknown  206, 207  
15  1985  60-100 Afrikaner female. Spontaneous tonsillar hemorrhage at age 5, frequent epistaxis, prolonged bleeding after tooth extractions. Excessive menstrual bleeding controlled by OCP. Gross morphological platelet abnormalities, many “bizarre and giant forms.” Sister and two brothers also with BSS, two other brothers normal. Mother's family “bleeders.” Sister had near-fatal bleeding during childbirth. Affected siblings required lifelong transfusions; in adulthood, only following surgical procedures or severe trauma. Splenectomy in proband and two siblings appeared to reduce the number of severe bleeding episodes.  Unknown  158 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
16  1985  120 Afrikaner female. History of excessive and prolonged bleeding from childhood following minor injury. Marked menorrhagia. Transfusions required for tooth extractions, surgical procedures, after dilation and curettage and a thyroidectomy at age 21.  Unknown  158  
17 1986   81  Male. Bolzano variant. Life-long history of epistaxis and gingival bleeding. Bleeding episodes continued after splenectomy at age 9 for thrombocytopenia. BT = 9 min. Sister died at age 2 from intracranial bleeding. Patient also homozygous for Thr145 → Met Koa polymorphism. Parents normal.  GP Ibα, homo. GCT → GTT, Ala156 → Val.  76, 208  
18 1986   62  Male. History of easy bruising, ecchymoses, and profuse bleeding from cuts. Mother bruises easily, father asymptomatic.  Unknown  208  
19  1987  38-67 Male. History of subcutaneous hematomas following injury. Prolonged bleeding after appendectomy. BT >15 min. Large platelets, no RIPA. Brother also BSS. No family history of bleeding.  Unknown  209 
20  1987  100  Swiss female. Suffered from epistaxis, gingival bleeding, ecchymoses, frequent menorrhagia. Splenectomy and steroid treatment for suspected ITP ineffective. Giant platelets and no RIPA. Six other family members heterozygous for BSS. Unknown  167  
21  1988  10-30  French-Canadian brother and sister with BSS, parents and other sister are normal. Unknown  206  
22  1988  25-100  Male. Life-long history of easy bruising, recurrent epistaxis and occasional petechiae. Giant platelets, no aggregation to ristocetin or bovine vWF. Presented at age 14 with thrombocytopenia and bleeding following tooth extraction; required blood and platelet transfusions. Initially diagnosed as ITP; ineffective prednisolone treatment. At age 18, elective splenectomy lessened severity of subsequent epistaxis. DDAVP apparently shortened bleeding time.  Unknown  168  
23  1988 25-30  Caucasian female. Life-long history of easy bruising, frequent epistaxis, occasional gum bleeding, and menorrhagia. Prolonged bleeding after dental extractions. Large platelets, BT >20 min. Refractory to platelets from random donors. Developed three red cell alloantibodies secondary to transfusions. OCP controlled menorrhagia and resulted in “less bruising and less frequent epistaxes.” DDAVP treatment was apparently ineffective. Sister also with BSS. Unknown  159  
24  1989   28  Caucasian female. Multiple blood or platelet transfusions after trauma or surgery. Abnormal RIPA, giant platelets. Hospitalized at 32 wk gestation, pelvic ultrasound showed fetal ascites and pericardial effusion. Isoimmunity suppressed by steroids and i.v. gamma globulin. Plasmapheresis allowed additional platelet transfusion. Gingival bleeding and ecchymotic suprapubic amniocentesis site. Amniocentesis led to premature membrane rupture. Chorioamnionitis 3 days later resulted in spontaneous labor (platelet count 8,000/μL). Excessive vaginal bleeding 3 wk after caesarean delivery; hysterectomy. Brother also with BSS. Parents second cousins.  Unknown  161  
25 1989  7-138  Male. Life-long abnormal bleeding, prolonged gingival bleeding. Uncomplicated cesarean birth and circumcision. Thrombocytopenia (45,000/μL) at age 14 mo, BT >21 min. Splenectomy at age 3. Recurrent childhood epistaxis and ecchymoses, excused from physical education. Bleeding symptoms decreased at puberty, bled from tooth extractions at age 23. Worked as meatcutter from age 20 without major bleeding episodes. At age 30, painless upper GI bleeding required transfusions, as did facial lacerations following car accident. Brother, sister, and two children normal; no family history of bleeding.  Unknown  210  
26  1990   Female. Excessive bleeding after tonsillectomy, menorrhagia, epistaxis and profuse bleeding associated with ear piercing. Younger brother also BSS with frequent epistaxis, once requiring hospitalization. Parents, two other siblings and five children normal.  Unknown. Probably not GP Ibα defect based on RFLP.  211  
27  1990   25 Spanish male. Life-long mucocutaneous bleeding, BT >30 min. Thrombocytopenia progressively worse from 120,000/μL in 1976. Splenectomy at age 6. Other family members normal.  GP Ibα, homo. TGC → AGC, Cys209 → Ser.  199, 212 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
28  1990  32  Male. Life-long bleeding tendency, frequent spontaneous epistaxes and mucosal hemorrhages requiring transfusions. Giant platelets with prominent granulations.  GP Ibα, hetero. TGG → TGA, Trp343 → stop in one allele, other defect unknown. 198  
29  1990   48  Danish female. Frequent epistaxes, ∼30% normal level of GP Ibα. BT = 11 min. No RIPA. Sisters aged 19 and 9 also BSS, BTs of 12 and 13 min, respectively. One sister bled profusely following dental extractions.  Unknown 213  
30  1990   32  Danish female. Microscopic hematuria, ∼7% normal level of GP Ibα. BT = 20 min (7 min at original diagnosis). No RIPA. Sister aged 71 also BSS, BT = 7 min. Consanguineous parents.  Unknown  213  
31  1990  47  Danish female. Severe bleeding at delivery, GP Ibα ∼22% normal level. BT = 11.5 min, no RIPA.  Unknown 213  
32  1990   64  Danish male. Numerous episodes of GI bleeding, ∼16% normal level of GP Ibα. BT = 8.5 min, no RIPA.  Unknown  213  
33  1991   51 Swedish female. Mild hypothyroidism and, since age 6, insulin-dependent diabetes mellitus. At 30 mo, subcutaneous hematoma on forehead, incision resulted in week-long bleeding. Frequent epistaxes and profuse menstrual bleeding. At age 20, repeated blood transfusions for bleeding associated with IUD use. At age 32, anemia. Giant platelets, absent RIPA. BT >20 min, some response to DDAVP. Father and three brothers normal, mother with menorrhagia.  Unknown  171 
34  1991  10-65  Swedish male, Karlstad variant. Thrombocytopenia from early childhood, life-long bleeding symptoms, severe gastric hemorrhage, subcutaneous hematomas, epistaxes and easy bruising. Bilateral subdural hematomas following violent sneeze. Giant platelets, no RIPA, low GP Ibα by flow cytometry. Corticosteroid treatment for ITP was ineffective and was discontinued. Splenectomy resulted in increased platelet count from 40,000 to 65,000/μL. BT >20 min, some beneficial effect of DDAVP. Normal number of megakaryocytes in bone marrow. Mother died of puerperal hemorrhage at childbirth. Parents with common ancestry from late seventeenth century. GP Ibα, homo. TGG → TGA, Trp498 → stop.  122, 171 
35  1992   80  Caucasian male. Frequent epistaxes, once resulting in hospitalization. Diagnosed prior to dental extraction because of thrombocytopenia. Mother had long history of bleeding, including bleeding associated with tonsillectomy, epistaxes, severe menorrhagia requiring hysterectomy, and GI bleeding. Autosomal dominant.  GP Ibα, hetero. CTC → TTC, Leu57 → Phe.  75 
36  1993   Female. Life-long bleeding tendency, frequent episodes of mucosal bleeding, particularly melena. Two siblings affected, one sister unaffected. Giant platelets, no RIPA, membrane GP Ib deficient by immunostaining.  GP IX, compound hetero. GAC → GGC, Asp21 → Gly; AAC → AGC, Asn45 → Ser.  114 
37  1993   Japanese female. General anaesthesia induced by fentanyl and diazepam, and maintained with nitrous oxide, fentanyl and 0.5% enflurane without exacerbating the bleeding tendency.  Unknown 173  
38  1994   24  Japanese female. Diagnosed BSS by giant platelets, no RIPA, thrombocytopenia and GP Ib deficiency. BT = 15 min. Parents normal, elder sister also with BSS. Parents consanguineous.  GP Ibα, homo. TCA → TAA, Ser444 → stop. 197  
39  1994  30-60  Caucasian male. Life-long bleeding tendency and epistaxes. Giant platelets, no RIPA and increased BT. Mother had mild bleeding, father and sister normal, brother with mild thrombocytopenia but no bleeding.  GP IX, homo. AAC → AGC, Asn45 → Ser.  214  
40  1994  35  Caucasian male. Severe life-long bleeding, mainly epistaxes and hematomas requiring multiple blood transfusions. Giant platelets, BT >20 min. Splenectomy at age 4 decreased bleeding tendency and obviated transfusions, but severe epistaxis returned at age 37 associated with physical exertion. Controlled by intranasal tranexamic acid.  GP Ibα, homo. Deletion of T in codon 76, frame shift and truncation after 19 residues.  172  
41  1994  75  Japanese female. Spontaneous epistaxes from early childhood, menorrhagia. ITP diagnosed at age 16, ineffective corticosteroid therapy and splenectomy. Giant platelets, no RIPA, GP Ib deficient by SDS-PAGE. Brother has mild thrombocytopenia, but no bleeding. Parents consanguineous.  GP IX, homo. TGG → TGA, Trp126 → stop.  116, 215 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
42  1994  58  Male. Thrombocytopenia and prolonged BT not corrected by DDAVP or tranexamic acid. History of mild purpura and an episode of prolonged gingival bleeding following a blow to the mouth at age 2. Steroid treatment ineffective. Brother diagnosed as ITP at age 4 after severe hematemesis, intermittent petechiae. Both brothers no RIPA, BT >15 min. Parents normal.  Unknown  169  
43  1994  65  Female. Petechiae, giant platelets, no RIPA. BT >45 min, decreased to 6.5 min for 4-5 h after i.v. DDAVP. Sister also BSS, platelet count 45,000/μL, BT = 18 min (5 min after DDAVP).  Unknown  174  
44  1995  100-150  Male. Nancy I variant. Life-long bleeding, bruising and epistaxes requiring platelet and erythrocyte transfusions, BT >10 min. Giant platelets and no RIPA. Brother and sister also affected. Parents and other brother normal.  GP Ibα, homo. CTC (Leu179) deleted.  216 
45  1995   42  Japanese female. Severe menorrhagia and life-long bleeding. Initially diagnosed as ITP, ineffective corticosteroid therapy and splenectomy. Diagnosed as BSS at age 26 by low platelet count, giant platelets, no RIPA and GP Ib deficiency. At ages 27 and 29, vaginal childbirth accompanied by platelet transfusions. Parents consanguineous.  GP Ibα, homo. One base deletion in AAAAAAA sequence, 58-residue frame shift and premature stop.  116  
46  1995   83  Male. Velo-cardio-facial syndrome with neonatal mild congestive heart failure due to conoventricular septal defect, thrombocytopenia. Abnormal bleeding from cardiac catheterization (18 mo) and circumcision (age 3), recurrent otitis media, delayed speech. Large platelets, diminished RIPA, epistaxis. Markedly low GP Ibα by flow cytometry.  GP Ibβ, compound hetero. C → G mutation at −133 (GATA site), other β allele deleted.  182  
47  1995   Male. Diagnosed at age 7 with severe mucocutaneous hemorrhage. Low platelet count, giant platelets and reduced prothrombin consumption. History of repeated epistaxes and severe post-traumatic hemorrhage. Many platelet transfusions led to anti-HLA and anti-GP Ib alloimmunization and hepatitis B and C infection. Hospitalized due to severe anemia and intermittent melena. Upper endoscopy revealed esophagogastric ecchymoses, angiodysplasia of the duodenum, and vascular ectasias and purpuric ecchymoses of cecum and colon.  Unknown  217  
48 1996   Japanese female. Bleeding tendency since childhood, menorrhagia. Found to be thrombocytopenic at second pregnancy (age 27), no RIPA, giant platelets. Childbirth accompanied by platelet transfusion. Sister also BSS. Parents first cousins.  GP IX, homo. TGT → TAT, Cys73 → Tyr.  121  
49  1996  Japanese male. Life-long bleeding, episodes of severe spontaneous epistaxes. Diagnosed as ITP (aged 9), prednisolone without effect. At age 23, bled in lungs and diagnosed BSS. Giant platelets, no RIPA, low GP Ib levels. Father also BSS, paternal aunt died of blood loss, aged 7. Parents and paternal grandparents consanguineous. GP IX, homo. TGT → TAT, Cys73 → Tyr.  121  
50 1996  30-50  Caucasian male. Bleeding disorder from early childhood, bled from tonsillectomy. Near-fatal bleeding as adult from splenectomy for suspected ITP. Recurrent bruising and severe GI bleeding often requiring hospitalization and blood or platelet transfusion. Treated with ε-aminocaproic acid. BT >20 min. Mother, sister, daughter normal. Parents consanguineous.  GP Ibα, homo. AAG → AGA, Lys19 → Arg due to A deletion, frame shift, stop at codon 21.  170  
51  1997  183-246  Japanese female. Variant form of BSS. Frequent spontaneous epistaxes during childhood. Later, bleeding tendency diminished and no epistaxes or menorrhagia. Giant platelets, BT = 9.5 min, no RIPA or botocetin-induced aggregation in PRP. Both near normal with washed platelets. Diagnosed with type 2A vWD. GP Ibβ not disulfide linked to GP Ibα. Younger sister clinically similar. Parents with no bleeding history. Mother's platelets moderately enlarged, father's normal.  GP Ibβ, compound hetero. TAC → TGC, Tyr88 → Cys; GCC → CCC, Ala108 → Pro.  183  
52  1997   60  Japanese female. History of bleeding, recurrent epistaxes, and melena from early childhood. Giant platelets, no RIPA, BT >15 min. Parents consanguineous. No family history of bleeding.  GP Ibα, homo. TG deletion at 972-975 of gene, frame shift after Thr294, premature stop. 218  
53  1997   25  Japanese male. History of recurrent epistaxes and melena from early childhood. Giant platelets, BT >15 min. Parents consanguineous. No family history of bleeding, but father had low platelet count.  GP Ibα. compound hetero. T insertion at 1418; A deletion in AAAAAAA (1438-44), truncation. Both lead to premature termination.  218 
Case No.  Year-150 Platelet Count-151 Clinical Description  Genetic Defect  Ref.  
54  1997  50-75 Male. Life-long bleeding tendency, spontaneous epistaxes up to age 20, then decreased. Splenectomy at age 24. After age 35, gingival bleeding with variable frequency and severity. Melena over 6 wk period at age 43 required hospitalization, but not transfusions. Giant platelets, no RIPA, BT = 4.5-6 min. Parents (first cousins) with no bleeding history.  GP IX, homo. TTT → TCT Phe55 → Ser in leucine-rich repeat.  219  
55  1997  20-30  Caucasian male. Mother and paternal grandfather of German descent. Large platelets and profuse bleeding tendency requiring frequent transfusions. No RIPA. BT >15 min. Large amounts of glycocalicin in plasma. Brother and sister were normal.  Same as case 7. 176 

Abbreviations: BSS, Bernard-Soulier syndrome; ITP, idiopathic thrombocytopenic purpura; OCP, oral contraceptive; PRP, platelet-rich plasma; BT, bleeding time (normal, <5 minutes); RIPAS, ristocetin-induced platelet aggregation; vWF, von Willebrand factor; vWD, von Willebrand disease.

Consanguinity of parents, where known, is also indicated.

F0-150

Year first reported.

F0-151

Platelet count × 10−3/μL (normal range, 150 to 250).

Studies in transfected cells have also proved useful for determining how the polypeptides interact with each other. From such studies, it has been demonstrated that GP Ibα and GP Ibβ are able to interact in the absence of the other polypeptides, as are GP Ibβ and GP IX.112 Thus, GP Ibβ is the polypeptide bridging the interaction between GP Ibα and GP IX, at least initially, because no interaction between the later 2 polypeptides could be detected in the absence of GP Ibβ. In contrast, antibody inhibition studies of platelet lysates and purified GP Ib-IX complex suggest that GP IX is more strongly associated with GP Ibα than with GP Ibβ.123 Confocal microscopy and expression studies indicate that the interaction of GP V with GP Ib-IX is through a direct link with GP Ibα.47 This association has a direct functional consequence, because expression of GP V in cultured cells is required for the complex to bind thrombin with high affinity, even though the site of thrombin binding is on GP Ibα.82 

The polypeptides of the complex all associate soon after their synthesis and insertion into the membrane of the endoplasmic reticulum.124 Before the complex reaches the cell surface, which in cultured cells takes approximately 3 hours,124 its polypeptides undergo a number of posttranslational modifications, including the addition of both N- and O-linked carbohydrate, modification of the intracytoplasmic cysteines of GP Ibβ and GP IX by acylation with fatty acids, and sulfation of tyrosines in the ligand-binding domain of GP Ibα. These modifications are all likely to influence the functions of the complex, and it is probable that mutations that disrupt any of the posttranslational modifications in vivo will result in variant forms of BSS.

GENES ENCODING THE GP Ib-IX-V POLYPEPTIDES

A separate gene encodes each component of the GP Ib-IX-V complex receptor. Like the polypeptides of this complex, the genes share a number of structural features (Fig 3). All except the gene for GP Ibβ contain the entire coding sequence within one exon45,125,126; the GP Ibβ gene contains an intron 10 bases after the start of the coding sequence.25 All are also relatively devoid of introns, with only the GP IX gene containing more than 1 (it contains 2).126 These genes share this compact structure and paucity of introns with other genes of the leucine-rich repeat family, the best example being the gene for oligodendrocyte-myelin glycoprotein, which contains one small intron in its 5′ untranslated region and the entire coding region in 1 exon.127 Despite their structural similarity, the genes encoding the GP Ib-IX-V polypeptides are not clustered in 1 region of the human genome. The GP Ibα gene is located on the short arm of chromosome 17,23 the GP Ibβ gene is on the long arm of chromosome 22,24 and the GP IX and GP V genes are located on the long arm of chromosome 327 (3q21 and 3q29, respectively; Fig 3).

Fig. 3.

Structures of the genes encoding the 4 polypeptides of the GP Ib-IX-V complex with exons shown as boxes, introns as the lines between boxes, and open reading frames in black. The position of the ATG start codon is also indicated.

Fig. 3.

Structures of the genes encoding the 4 polypeptides of the GP Ib-IX-V complex with exons shown as boxes, introns as the lines between boxes, and open reading frames in black. The position of the ATG start codon is also indicated.

Expression of the GP Ib-IX-V complex is limited to a very small number of tissues, the only major constitutive expression being in megakaryocytes and platelets. This complex may also be expressed in endothelial cells, although this is a matter of controversy. There have been reports of low level expression of GP Ibα in endothelial cells,128,129 expression that can be enhanced by the inflammatory cytokine, tumor necrosis factor-α.130,131Further evidence for expression of GP Ibα in endothelium was obtained by the cloning of a GP Ibα cDNA from an endothelial cell library.131 This cDNA was virtually identical to the original GP Ibα cDNA cloned from a HEL cell library.31More recently, Wu et al20 have provided evidence that endothelial cells, in culture and in vivo, express the full GP Ib-IX-V complex. One difference with the platelet complex is in the nature of GP Ibβ. Kelly et al24 found a polypeptide in endothelial cells that reacted with GP Ibβ antisera, but that migrated at a higher molecular mass (∼50 kD) than the platelet polypeptide (∼25 kD). They also cloned a cDNA that encoded a polypeptide with an amino terminus unrelated to platelet GP Ibβ but fused in frame with the platelet sequence such that the new polypeptide also contained essentially all of the platelet sequence. This interpretation of the data has since been challenged by Zieger et al,132 who also cloned a cDNA containing the GP Ibβ sequence. They identified a new gene immediately 5′ to the GP Ibβ gene that produced 2 transcripts, 1 containing the GP Ibβ sequence. The latter transcript presumably arose because the 5′ gene contains a suboptimal polyadenylation sequence. Hence, the transcription machinery sometimes reads through it and into the GP Ibβ gene, eventually using the GP Ibβ polyadenylation sequence. The resulting transcript thus also contains the GP Ibβ sequence, albiet out of frame, a finding at odds with that of Kelly et al.24 

One potential function for the complex expressed in endothelial cells derives from the work of Beacham et al,133 who suggested that the complex can mediate attachment of endothelial cells to vWF. Bombeli et al134 also recently proposed a role for endothelial cell GP Ibα in adhesion of activated platelets to umbilical vein endothelial cells. Others have not been able to demonstrate GP Ib-IX-V–mediated attachment of endothelial cells to vWF and have even called into question whether these cells have significant levels of complex expression.135 If, how, and when the GP Ib-IX-V complex is expressed in endothelial cells are thus still open questions in need of more investigation. Such expression of the GP Ib-IX-V complex in endothelium in vivo may depend on such variables as regional shear stresses, the presence of inflammatory cytokines, and the particular vascular bed from which the cells are derived.

At least part of the restricted expression of the GP Ib-IX-V complex can be ascribed to the unusual structure of the promoter regions of its genes. None of the promoters contain functional TATA or CAAT boxes, consensus transcription factor-binding sequences found in a high percentage of eukaryotic genes (GP V does contain 2 potential TATA boxes, but primer-elongation studies did not show transcripts of the expected sizes45). Instead, these promoters contain binding sites for the GATA and ETS families of transcription factors, a feature shared with other genes expressed in cells of megakaryocytic and erythroid lineages.136-142 Neither GATA nor ETS is specific for megakaryocytes; it has been suggested that particular combinations and relative levels of the GATA and ETS families are what determine megakaryocyte specificity.138,140 This specificity may also be related to transcriptional cofactors. Recently, a transcription factor named FOG (Friend of GATA-1) was described, which acts as a cofactor for GATA-1 during both erythroid and megakaryocytic cell differentiation.143 Together, the 2 transcription factors may stimulate transcription in a context-specific manner.144 

The importance of these factors for transcription of the GP Ib-IX-V genes is demonstrated by both synthetic and natural mutations. Mutations of both the GATA and ETS binding sequences in the promoters of GP Ibα and GP IX have been shown to reduce or abolish reporter gene expression in human erythroleukemia cells.141,142Likewise, a single-base mutation of the GATA-1 site in the GP Ibβ promoter markedly reduced expression of GP Ibβ and caused BSS in a patient with deletion of the other GP Ibβ allele and velo-cardio-facial syndrome.115 

POLYMORPHISMS AFFECTING THE GENES AND POLYPEPTIDES OF THE GP Ib-IX-V COMPLEX

Several polymorphisms of the GP Ib-IX-V complex have been described, affecting primarily the GP Ibα gene. In addition to potentially affecting the structure and functions of the complex, these polymorphisms serve as useful linkage markers for the genes affected.

The first described polymorphism of the complex was a variable number of tandem repeats (VNTR) polymorphism affecting the region encoding the GP Ibα macroglycopeptide.36,37,145,146 The 4 alleles vary in the number of tandem repeats of a 39-nucleotide sequence, which is present either 1, 2, 3, or 4 times in the different alleles.36,37 The resulting polypeptides specified by these alleles contain different numbers of 13-amino acid repeats in their macroglycopeptide region. Each repeat contains 5 potential sites forO-glycosylation, a modification predicted to add approximately 6 kD to the mass of the macroglycopeptide and 32 Å to its length.36 This VNTR polymorphism is the most informative as a genetic marker because of the high frequency of heterozygosity at this locus (25% to 30% in most populations).36 The frequencies of the different alleles vary widely in different ethnic populations, although the variant with 2 repeats (C variant) is the most common in all populations studied.22 

Another polymorphism of GP Ibα results in dimorphism at residue 145, with either Thr or Met occupying this position. The allele frequencies have been reported to be 90% and 10%, respectively, for the Thr and Met codons in both European and Japanese populations.147,148 This marker is closely linked to the VNTR polymorphism, with Met at position 145 being found only associated with the 3 largest size variants.37,149,150 Thus, this marker might be of use in determining heterozygosity in someone homozygous for the larger VNTR alleles. This marker has the additional advantage that the products of its alleles can be recognized on platelets with antisera, because this polymorphism accounts for the HPA-2 (or Ko) alloantigen system.147,148 

Recently, 2 more polymorphisms of the GP Ibα locus were described, the RS system, its alleles specifying either C or T at position −5 from the ATG start codon,151 and a nucleotide dimorphism (A or G) of the third base of the codon for Arg358.151,152 The degree of association between these markers and the other GP Ibα polymorphisms has yet to be determined.

To analyze for possible linkage of the BSS phenotype with the GP Ibβ locus, markers used in the analysis of the Di George and velo-cardio-facial syndromes can be used.153-156 As yet, no markers are available for the GP IX or GP V genes.

BSS: CLINICAL MANIFESTATIONS, DIAGNOSIS, AND THERAPY

BSS is extremely rare. In the populations of Europe, North America, and Japan, which have been studied most intensively, a prevalence of less than 1 in 1,000,000 can be estimated from cases reported in the literature. No doubt, this is an underestimate due to misdiagnosis and underreporting, but the low frequency of reported cases nevertheless is an indication of the rarity of the disorder. Perhaps one reason for this low prevalence is that, despite the potential for the disorder to be caused by mutation of any of 3 genes (and perhaps 4), the compactness of these genes decreases the frequency at which they are subject to random mutation. The lack of introns interrupting the coding sequence also greatly decreases the possibility that missplicing will cause deficiency of the encoded polypeptides. The low frequency of mutation at these loci is reflected also in the fact that the majority of the reported cases are homozygous for the same allele, having inherited 2 mutant alleles from parents who are blood relatives. The clinical features of the BSS patients reported to date are summarized in Table 1. Based on this relatively small number of reported cases, there appears to be no gender preference for BSS (47 of 88 patients described in Table 1 are female), as one would expect from an autosomal disorder. Of the patients in Table 1 for whom ethnicity was reported, 49 are Caucasian, 13 are Japanese, and 4 are of other ethnic groups.

Inheritance.

Inheritance of the BSS is usually autosomal recessive and is often associated with consanguinity (Table 1). Heterozygous family members may show about half the normal levels of platelet GP Ib-IX-V expression, but with no bleeding diatheses or only mild bleeding. Autosomal dominant inheritance has been reported in only 1 family.75 

Clinical manifestations.

BSS is characterized clinically by a prolonged skin bleeding time, morphologically enlarged platelets, and thrombocytopenia (Table 1 and reviewed in Dunlop et al157). Clinical manifestations commonly include frequent episodes of epistaxis, gingival and cutaneous bleeding, and hemorrhage associated with trauma. Although these characteristics are typical, comparisons of the clinical profiles of BSS patients reveal considerable variation between individuals. Platelet counts may range from very low (<30,000/μL) to marginally low or normal (∼200,000/μL) and in individual patients may fluctuate considerably over a period of years. Skin bleeding times may range from only marginally prolonged (5 to 10 minutes) to greater than 20 minutes. Bleeding tendencies associated with BSS are usually evident from early childhood. However, the severity of symptoms may progressively worsen or become alleviated throughout puberty and adult life. Most often, severe bleeding episodes are associated with tonsillectomy, appendectomy, splenectomy, other surgical procedures, dental extractions, menses and pregnancies, or accidents. Ecchymoses without significant trauma are relatively common, as are episodes of spontaneous epistaxis and gingival and gastrointestinal bleeding. Menorrhagia in premenopausal women is of variable severity and may be controlled in some cases by oral contraceptives.13,158,159Pregnancy in BSS patients may be relatively uneventful or may present complications of varying severity.116,121,122,158,160-166Bleeding associated with childbirth is generally supported by blood and/or platelet transfusions and may necessitate hysterectomy to control bleeding.161 Multiple childbirth is not uncommon.116,121 

Diagnosis.

Congenital platelet disorders related to platelet adhesion, activation, secretion, aggregation, or number and various coagulopathies are often not distinguishable from their clinical manifestations alone, presenting a challenge to diagnosis that often requires specialized tests or biochemical analyses. For example, BSS has frequently been misdiagnosed as idiopathic thrombocytopenic purpura (ITP),116,121,167-170 based on a prolonged bleeding time and thrombocytopenia, and often is treated unsuccessfully with steroids or splenectomy. The initial laboratory assessment of BSS should involve measurement of blood cell counts and examination of a blood smear for thrombocytopenia and morphological abnormalities of platelets. BSS can usually be differentiated experimentally from other bleeding disorders by functional analysis of stirred platelet suspensions in an aggregometer. The characteristic abnormality in BSS is an isolated defect in ristocetin-induced agglutination. Unlike the defect in von Willebrand disease, this abnormality is not corrected by the addition of normal plasma. Platelet aggregation in response to other agonists, such as collagen and ADP, as well as clot retraction, is usually normal. The provisional diagnosis based on aggregometry should be confirmed biochemically (reviewed in Dunlop et al157). This may involve assessment of platelet surface glycoprotein expression by flow cytometry, surface-labeling of washed platelets followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography, or immunoblotting of platelet lysates with specific antiplatelet glycoprotein antibodies. Finally, establishing an abnormal genotype by molecular studies may allow precise definition of the abnormality causing the platelet defect, as discussed below.

Therapy.

The therapeutic approaches to the management of patients with BSS involve both general supportive measures and specific treatment of bleeding episodes. General measures include educating the patients about their bleeding diathesis and the importance of avoiding even relatively minor trauma and advising them against the use of antiplatelet medications such as aspirin. Adequate dental hygiene should be maintained to prevent gingival disease and to minimize dental procedures. Iron deficiency may result from chronic gingival bleeding or menorrhagia and should be treated. In some cases, splenectomy has apparently been beneficial in moderating thrombocytopenia and the severity of clinical symptoms,158,168,171,172 although this treatment should be avoided because of the high risk for perisurgical hemorrhage and the lack of controlled data to support its use. Control of bleeding episodes or prophylaxis for prevention of bleeding during surgical procedures usually requires transfusion of blood and/or platelets, despite the risk that these patients will develop antiplatelet and/or antierythrocyte alloantibodies.158,168,171,172 General anesthesia has been successful in a BSS patient, although anesthetics such as halothane or dibucaine that compromise platelet reactivity should be avoided.173 The use of antifibrinolytic drugs, such as ε-aminocaproic acid or tranexamic acid, may or may not be beneficial.169,170,172 DDAVP may shorten the bleeding time in some168,171,174 but not all159,169 BSS patients. The different responses of individual patients to these latter measures may reflect differences in the underlying disease, with those with milder forms of the disease more likely to respond to these therapies.

Because of the relative ease with which the molecular lesions can be determined and given the simplicity of the affected genes, BSS seems an ideal candidate disease for gene therapy. Such therapy would presumably involve transduction of a hematopoietic stem cell with a working copy of the defective gene, under the control of its own promoter or of another platelet-specific promoter. Among the questions to be answered before such therapy becomes reality is whether reconstituting the blood with only a relatively small proportion of normal platelets will be sufficient to ameliorate the bleeding diathesis associated with BSS.

BSS: CLASSIFICATION

The genetic defects underlying BSS so far determined (Table 1) are clearly heterogeneous, but may be broadly categorized in 2 ways. First, the abnormality may be either (1) a biosynthetic defect affecting synthesis, processing, or expression of the GP Ib-IX-V complex; or (2) a functional defect in which GP Ibα is expressed in a dysfunctional form that fails to bind ligand. Second, the genetic lesion may be localized to (1) the GP Ibα gene (chromosome 17pter-p12), (2) the GP Ibβ gene (chromosome 22q11.2), (3) the GP IX gene (chromosome 3q21), or possibly (4) the GP V gene (chromosome 3q29). The syndrome may conveniently be classified, therefore, as type 1a to indicate a defect of the GP Ibα gene that results in a biosynthetic defect, type 1b for a synthetic defect of the GP Ibβ gene, etc. The molecular defects thus far reported arise from missense, nonsense, or deletion mutations of the GP Ibα, GP Ibβ, or GP IX genes (Table 1) that produce truncated, unstable, or dysfunctional polypeptides.

INFORMATIVE MUTATIONS IN BSS AND PLATELET-TYPE VON WILLEBRAND DISEASE

Clearly, much remains to be learned about the cause of several phenotypic features of the BSS. Nevertheless, elucidation of the molecular basis of BSS and platelet-type von Willebrand disease has provided several very valuable insights into the synthesis and functions of the complex. A few of the more informative mutations will be reviewed in this section.

GP Ibα mutations.

Several mutations of GP Ibα provide interesting information regarding the functions of the GP Ib-IX-V complex. The Bolzano variant of BSS, caused by a substitution of Val for Ala at position 156 of GP Ibα, produces mutant complexes that appear on the cell surface essentially at normal levels.76 This mutant is unable to bind vWF normally, but binds thrombin with a similar affinity to that of the wild-type complex.175 The platelets of the patient with the Bolzano variant of BSS thus do not have the defect in the response to low concentrations of thrombin that most BSS platelets do. This finding suggests that the leucine-rich repeats have an important role in binding vWF, but not thrombin. Another interesting feature of this mutant is that it has no mutations of its cytoplasmic region that would be predicted to influence the association of the complex with the platelet cytoskeleton, yet the platelets of the affected patient are much larger than normal, indicating that the large platelets in BSS cannot be explained simply by a defective membrane-cytoskeletal association.

Only one instance of autosomal-dominant transmission of BSS has been described. The responsible mutation, Leu57→Phe, like the Bolzano mutation, affects the leucine-rich repeat region of GP Ibα and encodes a mutant polypeptide that appears on the cell surface, but, once there, is apparently abnormally susceptible to cleavage by plasma proteases.75 The dominant nature of this mutation suggests that the product of the mutant allele interferes with the functions of the wild-type polypeptide, giving further support for the existence of a vWF receptor containing more than 1 GP Ibα polypeptide.

Also of interest is the recently described deletion of the last 2 bases of GP Ibα codon 492, which results in a reading frame-shift within the region encoding the GP Ibα membrane-spanning segment, with the addition of 81 novel amino acids before the polypeptide reaches a premature stop. Two unrelated patients homozygous for this mutation were described simultaneously; both had a considerable amount of GP Ibα or a degradation product in their plasma, indicating that GP Ibα was synthesized normally but failed to be anchored in the plasma membrane.120,176 In addition to carrying the same mutation, these 2 patients had an identical haplotype, with identical sequences at 3 other polymorphic sites. The ancestors of both of these patients emigrated to the United States from Germany. Interestingly, a Finnish patient carrying an identical mutant haplotype was recently reported in abstract form.177 This mutant haplotype probably arose at least several centuries ago in the northern European population and will likely be a common mutation associated with the disorder in patients of northern European ancestry.

Platelet-type von Willebrand disease is another bleeding disorder caused by mutations affecting the GP Ib-IX-V complex, but in this case resulting in a dominant gain-of-function phenotype.60,61The resultant mutants bind vWF with high affinity and the paradoxical presence of a bleeding predisposition is due to clearance of the hemostatically most active large vWF multimers. The mutations described in this disorder (Gly233→Val59 and Met239→Val58,178,179) are found within a short linear sequence encompassing residues 233 to 239 of GP Ibα, a region that lies within the loop formed by a disulfide bond between Cys209 and Cys248 of GP Ibα (Fig 2). Molecular modeling studies of this region suggest that the mutations produce an active conformation of GP Ibα that is competent to bind vWF in the absence of modulators.180,181 These mutants thus provide clues as to changes that the receptor undergoes when platelets are exposed to shear or ristocetin.

GP Ibβ.

Two BSS variants that result from mutations of GP Ibβ are particularly informative. The first was described in a patient with velo-cardio-facial syndrome, a developmental disorder caused by deletion of the chromosomal region 22.11.2, which contains the gene for GP Ibβ.182 This patient's remaining GP Ibβ gene did not contain any mutations in the polypeptide coding region, but a single point mutation was found in the promoter region within a binding sequence for the GATA-1 transcription factor.115Transcription studies performed in cell lines demonstrated that the mutation decreased the transcription of a reporter gene sixfold. So far, this is the only reported case of BSS not caused by mutations of polypeptide coding regions.

Another interesting variant of BSS caused by mutations of the GP Ibβ gene was described in a Japanese patient with a very mild propensity for bleeding.183 This patient was a compound heterozygote for 2 mutations (Tyr88→Cys and Ala108→Pro). The platelets were not defective for agglutination by either ristocetin or botrocetin and had only slightly decreased surface levels of the GP Ib-IX-V complex. This patient's platelets were very large, and the only finding that could explain this abnormality was the failure of the normal disulfide linkage between GP Ibα and GP Ibβ, suggesting that the mutant complexes may have a signalling defect.

GP IX.

BSS caused by mutations in the gene for GP IX emphasize the importance of this polypeptide in the synthesis and surface expression of the entire GP Ib-IX-V complex. The first case of BSS reported to be due to such mutations was described by Wright et al114 in 3 siblings who were compound heterozygotes for mutations in the GP IX gene. Both alleles were affected by missense mutations of the GP IX leucine-rich repeat region (Asp21→Gly and Asn45→Ser), and the expression of the entire complex on the surfaces of their platelets was minimal. Expression of the mutants in cultured cells showed that both mutant polypeptides failed to associate with GP Ibβ or augment expression of GP Ib (α-β) on the cell surface, suggesting a role for the GP IX leucine-rich motif in polypeptide associations.184 

Bernard-Soulier variants.

In addition to the disorder produced by germline mutations, acquired BSS from somatic mutation of bone marrow stem cells has also been described. Two cases have been described in association with myelodysplasia (both in children),185,186 and 1 case was described in a patient with acute myelogenous leukemia (M6).186 In 1 patient with a myelodysplastic syndrome and monosomy 7, 2 populations of platelets were identified in her blood, 1 population of normal-sized platelets with normal levels of the GP Ib-IX-V complex on their surfaces and 1 of large platelets lacking the complex.185 The latter population was apparently produced by the abnormal marrow clone. This patient died of acute leukemia shortly after acquiring the disease.

BSS-like defects are also rarely seen associated with immune thrombocytopenia when the offending antibody interferes with vWF binding to the GP Ib-IX-V complex.187-189 In this situation, the bleeding risk is much greater than usually seen in immune thrombocytopenia because the hemostatic defect resulting from the low platelet count is compounded by the severe adhesive defect of the platelets that remain in circulation.

UNEXPLAINED PHENOMENA IN BSS

BSS platelets have several phenotypic features that remain poorly understood. One is their large size. An obvious explanation for this feature is provided by the altered plasma membrane–cytoskeletal interaction due to the absence of the GP Ib-IX-V complex on the platelet surface. Although this defect undoubtedly explains the increased deformability of the Bernard-Soulier platelet membrane,190 it may not be the cause of the abnormally large platelets in this syndrome. Several BSS patients have been described whose platelets are large but contain relatively normal surface levels of the complex. In 1 of these, the Bolzano variant, the GP Ibα polypeptide contains only a single amino acid substitution in its extracellular domain that affects vWF binding but not surface expression of the complex. These platelets presumably have a normal linkage with the cytoskeleton, although the possibility remains that the mutation changes the conformation of the cytoplasmic domain and influences that association.

These data would also seem to suggest a role for vWF binding in platelet production from megakaryocytes; however, such a role is ruled out by the observation that patients with severe (type 3) von Willebrand disease have normal-sized platelets. Consistent with this, another BSS variant with defective GP Ibα–GP Ibβ chain association produces large platelets and has relatively normal expression of the complex and vWF binding.183 These data suggest that the abnormality in BSS platelets that leads to their abnormal size may either be the failure of the GP Ib-IX-V complex to recognize a novel bone marrow ligand involved in platelet shedding or a disruption of the signalling pathways involved in this process. In this regard, BSS platelets have been reported to have decreased levels of phospholipase C activity.191 

The second phenotypic characteristic of BSS that has yet to be fully explained is the abnormality of the prothrombin consumption test in BSS platelets.192 The prothrombin consumption test detects deficiencies of factors V, VIII, IX, XI, or XII,193 more than 1 of which could contribute to the abnormality of this test in BSS. Accordingly, BSS platelets have been reported to be deficient in collagen-induced coagulant activity and to be unable to bind factor XI.6 In addition, the GP Ib-IX-V complex has recently been reported to be the platelet binding site for high molecular weight kininogen194 and for factor XII.195 Finally, the abnormal prothrombin consumption test with BSS platelets has been reported to be correctable by the addition of factor VIII. This latter finding is consistent with the GP Ib-IX-V complex providing a low-affinity receptor on platelets for vWF/factor VIII, a conjecture consistent with the observation that treating normal platelets with an anti-GP Ibα antibody that blocks vWF binding mimics the abnormality in the prothrombin consumption test seen in BSS platelets.196 In contrast to the abnormality in the early stages of contact activation, resting BSS platelets show enhanced prothrombinase activity8 due to increased levels of phosphatidylserine on their surfaces.

STRATEGIES FOR CHARACTERIZING MUTATIONS CAUSING BSS

Figure 4 presents an algorithm that can be used as a guide for the rational exploration of the molecular basis of BSS. Several features of this strategy will be discussed briefly here.

Fig. 4.

Algorithm for determining the genetic basis of BSS. Details are given in the text.

Fig. 4.

Algorithm for determining the genetic basis of BSS. Details are given in the text.

After a patient with the clinical characteristics of BSS has been identified, it is important to take as complete a medical history and family history as possible. Particularly important is a history of consanguinity in the parents. It is also vital to collect blood from as many of the relatives as possible, so as to be able to identify the affected gene and verify the mode of inheritance. Biochemical studies of the parents' platelets will also be useful in identifying the affected gene (discussed below).

The levels of the individual polypeptides on the patient's platelets should be determined by biochemical means to identify a candidate gene for sequencing. Quite often residual quantities of some of the polypeptides appear in the platelets of patients with a severe deficiency of one polypeptide. For example, in the GP IX mutants described by Wright et al,114 flow cytometry showed residual amounts of GP Ib in a subset of platelets, whereas GP IX was virtually undetectable; in BSS Kagoshima, due to truncation of GP Ιbα, residual GP IX and GP Ibβ were detected on the platelet surface.197 The polypeptide found to be most deficient by these assays will indicate which gene should be studied first by sequencing. Here too, studies of the parents' platelets may be useful. For example, in a patient severely deficient in all of the GP Ib-IX-V complex polypeptides whose parents are blood relatives, the finding of 2 bands for GP Ibα on immunoblots of platelets from 1 of the parents (indicating heterozygosity for the VNTR polymorphism) will rule out GP Ibα as the affected gene because the patient could not have inherited a defective GP Ibα allele from this parent. Similarly, if more than 1 patient in a family is affected, it is a relatively simple matter to rule out GP Ibα as the affected gene if any 1 of the affected individuals is heterozygous for the VNTR, or if any 2 are homozygous for different alleles. Homozygosity for this marker is not as informative; its predictive value is increased if the affected siblings are homozygous for all of the other GP Ibα polymorphisms, indicating that they inherited the same GP Ibα allele from both parents, an event with a probability of only 6.3% (for 2 siblings of heterozygous parents carrying the same mutant allele).

Several of the previously described mutations can be identified by restriction analysis of polymerase chain reaction (PCR)-amplified genomic DNA. One nonsense mutation of GP Ibα that produces a truncated polypeptide also ablates an Ava II site,198 a change that can be used as a marker for the presence or absence of the mutation. The C to T mutation that causes the Ala156→Val substitution responsible for the Bolzano variant of BSS introduces a new Hpa I site into the coding region of the GP Ibα gene,76 the Cys209→Ser mutation produces a new Mse I site,199 and the Leu129→Pro mutation eliminates a Sac I site.200 Both of the mutations of GP IX described by Wright et al114 (Asp21→Gly and Asn45→Ser) create new recognition sites for the enzyme Fnu4H1. Thus, several of the mutations known to be associated with BSS can be easily identified by restriction enzyme digestion of PCR-amplified DNA. If the restriction pattern indicates that the patient is heterozygous for 1 of the previously identified mutations, the other allele should be sequenced to identify the second mutation.

If this strategy fails to identify a candidate gene or no mutation is found in the suspected gene, the genes encoding all of the GP Ib-IX-V polypeptides can be sequenced. The relative simplicity of the gene structures makes direct sequencing the most straightforward approach for identifying mutations, particularly with the availability of automated sequencing. In addition, the paucity of intervening sequences obviates the need for reverse transcription of mRNAs, because the uninterrupted coding sequence can be obtained directly from genomic DNA (except in the GP Ibβ gene, which has only 1 small intron interrupting the coding region). The order of priority shown (GP Ibα > GP IX > GP Ibβ > GP V) is based on the relative frequency that the genes for the individual polypeptides have been found to be affected in reported cases of BSS. The GP V gene is given the lowest priority because it has not been reported as the affected gene causing BSS and because of the likelihood that the clinical sequelae of its absence will be less severe than those of the others. Failure to identify a mutation in any of the polypeptide coding regions suggests the possibility that the disorder is due to decreased transcription of 1 of the genes. The affected gene can be identified by the use of linkage markers to determine which of the genes is homozygous (in the offspring of a consanguineous union). The promoter regions of the gene identified by linkage markers can then be sequenced.

When an apparently homozygous mutation is identified in patients in whom the parents are not known to be consanguineous, it will be necessary to rule out a hemizygous situation in which the other allele has been deleted, rendering impossible its amplification by PCR. This is a particularly important concern with apparently homozygous mutations of the GP Ibβ gene, because this gene usually undergoes hemizygous deletion in velo-cardio-facial syndrome,182 a condition whose manifestations can be subtle.201 

Finally, when mutations are identified whose consequences are not obvious (eg, missense mutations), it is important that the causative nature of the mutation be demonstrated by expression and functional studies. Examples of some characterizations are given in the algorithm. Similarly, if a mutation is identified within 1 of the promoters that is believed to be responsible for decreased transcription, this should be determined by expression of the mutant promoter, perhaps directing the expression of a reporter gene in a megakaryocytic cell line.115,142,202 

The molecular characterization of patients with platelet-type von Willebrand disease should focus on the N-terminus of GP Ibα, in particular in the disulfide loop between Cys209 and Cys248, where the previous mutations were identified.58,59,178,179 

CONCLUSIONS

BSS is a rare but fascinating disorder. Since its clinical description in 1948, analysis of its functional and molecular defects has spawned much of our current understanding of the role of the GP Ib-IX-V complex as a key receptor in initiating hemostasis. The continued analysis of the molecular and genetic defects in BSS should provide further information on the topography and assembly of the GP Ib-IX-V complex, on the role of this complex in the interactions of vWF and thrombin with platelets, on how its ligation activates platelets, on its role in coagulation, and on its participation in regulating platelet size and turnover.

ACKNOWLEDGMENT

It is a pleasure to acknowledge the assistance of David Smith with the preparation of this review.

Supported by grants from the National Institutes of Health, the American Heart Association, and the National Health and Research Council of Australia.

Address reprint requests to José A. López, MD, Veterans Affairs Medical Center, Hematology/Oncology (111H), 2002 Holcombe Blvd, Houston, TX 77030; e-mail: josel@bcm.tmc.edu; or Michael C. Berndt, PhD, Baker Medical Research Institute, Commercial Road, Prahran, VIC 3181, Australia; e-mail: michael.berndt@baker.edu.au.

REFERENCES

REFERENCES
1
Bernard
J
Soulier
JP
Sur une nouvelle variété de dystrophie thrombocytaire-hémorragipare congénitale.
Semin Hop Paris
24
1948
3217
2
Gröttum
KA
Solum
NO
Congenital thrombocytopenia with giant platelets: A defect in the platelet membrane.
Br J Haematol
16
1969
277
3
Howard
MA
Hutton
RA
Hardisty
RM
Hereditary giant platelet syndrome: A disorder of a new aspect of platelet function.
Br Med J
4
1973
586
4
Caen
JP
Levy-Toledano
S
Interaction between platelets and von Willebrand factor provides a new scheme for primary haemostasis.
Nature
244
1973
159
5
Weiss
HJ
Tschopp
TB
Baumgartner
HR
Sussman
II
Johnson
MM
Egan
JJ
Decreased adhesion of giant (Bernard-Soulier) platelets to subendothelium. Further implications on the role of the von Willebrand factor in hemostasis.
Am J Med
57
1974
920
6
Walsh
PN
Mills
DC
Pareti
FI
Stewart
GJ
Macfarlane
DE
Johnson
MM
Egan
JJ
Hereditary giant platelet syndrome. Absence of collagen-induced coagulant activity and deficiency of factor-XI binding to platelets.
Br J Haematol
29
1975
639
7
Perret
B
Lévy-Toledano
S
Plantavid
M
Bredoux
R
Chap
H
Tobelem
G
Douste-Blazy
L
Caen
JP
Abnormal phospholipid organization in Bernard-Soulier platelets.
Thromb Res
31
1983
529
8
Bevers
EM
Comfurius
P
Nieuwenhuis
HK
Levy-Toledano
S
Enouf
J
Belluci
S
Caen
JP
Zwaal
RF
Platelet prothrombin converting activity in hereditary disorders of platelet function.
Br J Haematol
63
1986
335
9
Maldonado
JE
Gilchrist
GS
Brigden
LP
Bowie
EJ
Ultrastructure of platelets in Bernard-Soulier syndrome.
Mayo Clinic Proc
50
1975
402
10
White
JG
Inherited abnormalities of the platelet membrane and secretory granules.
Hum Pathol
18
1987
123
11
Nurden
AT
Caen
JP
Specific roles for platelet surface glycoproteins in platelet function.
Nature
255
1975
720
12
Clemetson
KJ
McGregor
JL
James
E
Dechavanne
M
Lüscher
EF
Characterization of the platelet membrane glycoprotein abnormalities in Bernard-Soulier syndrome and comparison with normal by surface-labeling techniques and high-resolution two-dimensional gel electrophoresis.
J Clin Invest
70
1982
304
13
Berndt
MC
Gregory
C
Chong
BH
Zola
H
Castaldi
PA
Additional glycoprotein defects in Bernard-Soulier's syndrome: Confirmation of genetic basis by parental analysis.
Blood
62
1983
800
14
Bernard
J
History of congenital hemorrhagic thrombocytopathic dystrophy.
Blood Cells
9
1983
179
15
Berndt
MC
Fournier
DJ
Castaldi
PA
Bernard-Soulier syndrome.
Clin Haematol
2
1989
585
16
Kroll
MH
Hellums
JD
McIntire
LV
Schafer
AI
Moake
JL
Platelets and shear stress.
Blood
88
1996
1525
17
Du
X
Beutler
L
Ruan
C
Castaldi
PA
Berndt
MC
Glycoprotein Ib and glycoprotein IX are fully complexed in the intact platelet membrane.
Blood
69
1987
1524
18
Modderman
PW
Admiraal
LG
Sonnenberg
A
von dem Borne
AEGK
Glycoproteins V and Ib-IX form a noncovalent complex in the platelet membrane.
J Biol Chem
267
1992
364
19
Michelson
AD
Benoit
SE
Furman
MI
Barnard
MR
Nurden
P
Nurden
AT
The platelet surface expression of glycoprotein V is regulated by two independent mechanisms: Proteolysis and the reversible cytoskeletal-mediated redistribution to the surface-connected canalicular system.
Blood
87
1996
1396
20
Wu
G
Essex
DW
Meloni
FJ
Takafuta
T
Fujimura
K
Konkle
BA
Shapiro
SS
Human endothelial cells in culture and in vivo express on their surface all four components of the glycoprotein Ib/IX/V complex.
Blood
90
1997
2660
21
Kobe
B
Deisenhofer
J
The leucine-rich repeat: A versatile binding motif.
Trends Biochem Sci
19
1994
415
22
López
JA
The platelet glycoprotein Ib-IX complex.
Blood Coagul Fibrinolysis
5
1994
97
23
Wenger
RH
Wicki
AN
Kieffer
N
Adolph
S
Hameister
H
Clemetson
KJ
The 5′ flanking region and chromosomal localization of the gene encoding human platelet membrane glycoprotein Ibα.
Gene
85
1989
517
24
Kelly
MD
Essex
DW
Shapiro
SS
Meloni
FJ
Druck
T
Huebner
K
Konkle
BA
Complementary DNA cloning of the alternatively expressed endothelial cell glycoprotein Ibβ (GPIbβ) and localization of the GPIbβ gene to chromosome 22.
J Clin Invest
93
1994
2417
25
Yagi
M
Edelhoff
S
Disteche
CM
Roth
GJ
Structural characterization and chromosomal location of the gene encoding human platelet glycoprotein Ibβ.
J Biol Chem
269
1994
17424
26
Hickey
MJ
Deaven
LL
Roth
GJ
Human platelet glycoprotein IX. Characterization of cDNA and localization of the gene to chromosome 3.
FEBS Lett
274
1990
189
27
Yagi
M
Edelhoff
S
Disteche
CM
Roth
GJ
Human platelet glycoproteins V and IX: Mapping of two leucine-rich glycoprotein genes to chromosome 3 and analysis of structures.
Biochemistry
34
1995
16132
28
Fox
JE
Aggerbeck
LP
Berndt
MC
Structure of the glycoprotein Ib-IX complex from platelet membranes.
J Biol Chem
263
1988
4882
29
Dong
J-F
Li
CQ
López
JA
Tyrosine sulfation of the GP Ib-IX complex: Identification of sulfated residues and effect on ligand binding.
Biochemistry
33
1994
13946
30
Ward
CM
Andrews
RK
Smith
AI
Berndt
MC
Mocarhagin, a novel cobra venom metalloproteinase, cleaves the platelet von Willebrand factor receptor glycoprotein Ibα. Identification of the sulfated tyrosine/anionic sequence Tyr-276–Glu-282 of glycoprotein Ibα as a binding site for von Willebrand factor and α-thrombin.
Biochemistry
35
1996
4929
31
Lopez
JA
Chung
DW
Fujikawa
K
Hagen
FS
Papayannopoulou
T
Roth
GJ
Cloning of the α chain of human platelet glycoprotein Ib: A transmembrane protein with homology to leucine-rich α2-glycoprotein.
Proc Natl Acad Sci USA
84
1987
5615
32
Kobe
B
Deisenhofer
J
Crystal structure of porcine ribonuclease inhibitor, a protein with leucine-rich repeats.
Nature
366
1993
751
33
Judson
PA
Anstee
DJ
Clamp
JR
Isolation and characterization of the major oligosaccharide of human platelet membrane glycoprotein GPIb.
Biochem J
205
1982
81
34
Tsuji
T
Tsunehisa
S
Watanabe
Y
Yamamoto
K
Tohyama
H
Osawa
T
The carbohydrate moiety of human platelet glycocalicin. The structure of the major ser/thr-linked chain.
J Biol Chem
258
1983
6335
35
Korrel
SA
Clemetson
KJ
Van Halbeek
H
Kamerling
JP
Sixma
JJ
Vliegenthart
JF
Structural studies on the O-linked carbohydrate chains of human platelet glycocalicin.
Eur J Biochem
140
1984
571
36
López
JA
Ludwig
EH
McCarthy
BJ
Polymorphism of human glycoprotein Ibα results from a variable number of tandem repeats of a 13–amino acid sequence in the mucin-like macroglycopeptide region. Structure/function implications.
J Biol Chem
267
1992
10055
37
Ishida
F
Furihata
K
Ishida
K
Yan
J
Kitano
K
Kiyosawa
K
Furuta
S
The largest variant of platelet glycoprotein Ibα has four tandem repeats of 13 amino acids in the macroglycopeptide region and a genetic linkage with methionine 145.
Blood
86
1995
1357
38
Lopez
JA
Chung
DW
Fujikawa
K
Hagen
FS
Davie
EW
Roth
GJ
The α and β chains of human platelet glycoprotein Ib are both transmembrane proteins containing a leucine-rich amino acid sequence.
Proc Natl Acad Sci USA
85
1988
2135
39
Wardell
MR
Reynolds
CC
Berndt
MC
Wallace
RW
Fox
JE
Platelet glycoprotein Ibβ is phosphorylated on serine 166 by cyclic AMP-dependent protein kinase.
J Biol Chem
264
1989
15656
40
Fox
JE
Berndt
MC
Cyclic AMP-dependent phosphorylation of glycoprotein Ib inhibits collagen-induced polymerization of actin in platelets.
J Biol Chem
264
1989
9520
41
Hickey
MJ
Williams
SA
Roth
GJ
Human platelet glycoprotein IX: An adhesive prototype of leucine-rich glycoproteins with flank-center-flank structures.
Proc Natl Acad Sci USA
86
1989
6773
42
Berndt
MC
Gregory
C
Kabral
A
Zola
H
Fournier
D
Castaldi
PA
Purification and preliminary characterization of the glycoprotein Ib complex in the human platelet membrane.
Eur J Biochem
151
1985
637
43
Muszbek
L
Laposata
M
Glycoprotein Ib and glycoprotein IX in human platelets are acylated with palmitic acid through thioester linkages.
J Biol Chem
264
1989
9716
44
Schick
PK
Walker
J
The acylation of megakaryocyte proteins: Glycoprotein IX is primarily myristoylated while glycoprotein Ib is palmitoylated.
Blood
87
1996
1377
45
Lanza
F
Morales
M
de La Salle
C
Cazenave
J-P
Clemetson
KJ
Shimomura
T
Phillips
DR
Cloning and characterization of the gene encoding the human platelet glycoprotein V. A member of the leucine-rich glycoprotein family cleaved during thrombin-induced platelet activation.
J Biol Chem
268
1993
20801
46
Hickey
MJ
Hagen
FS
Yagi
M
Roth
GJ
Human platelet glycoprotein V: Characterization of the polypeptide and the related Ib-V-IX receptor system of adhesive, leucine-rich glycoproteins.
Proc Natl Acad Sci USA
90
1993
8327
47
Li
CQ
Dong
J-F
Lanza
F
Sanan
DA
Sae-Tung
G
López
JA
Expression of platelet glycoprotein (GP) V in heterologous cells and evidence for its association with GP Ibα in forming a GP Ib-IX-V complex on the cell surface.
J Biol Chem
270
1995
16302
48
Berndt
MC
Phillips
DR
Purification and preliminary physicochemical characterization of human platelet membrane glycoprotein V.
J Biol Chem
256
1981
59
49
Springer
TA
Adhesion receptors of the immune system.
Nature
346
1990
425
50
Sixma
JJ
Sakariassen
KS
Stel
HV
Houdijk
WP
In der Maur
DW
Hamer
RJ
de Groot
PG
van Mourik
JA
Functional domains on von Willebrand factor. Recognition of discrete tryptic fragments by monoclonal antibodies that inhibit interaction of von Willebrand factor with platelets and with collagen.
J Clin Invest
74
1984
736
51
Fujimura
Y
Titani
K
Holland
LZ
Russell
SR
Roberts
JR
Elder
JH
Ruggeri
ZM
Zimmerman
TS
von Willebrand factor. A reduced and alkylated 52/48-kDa fragment beginning at amino acid residue 449 contains the domain interacting with platelet glycoprotein Ib.
J Biol Chem
261
1986
381
52
Andrews
RK
Gorman
JJ
Booth
WJ
Corino
GL
Castaldi
PA
Berndt
MC
Cross-linking of a monomeric 39/34-kDa dispase fragment of von Willebrand factor (Leu-480/Val-481-Gly-718) to the N-terminal region of the α-chain of membrane glycoprotein Ib on intact platelets with bis(sulfosuccinimidyl) suberate.
Biochemistry
28
1989
8326
53
Titani
K
Kumar
S
Takio
K
Ericsson
LH
Wade
RD
Ashida
K
Walsh
KA
Chopek
MW
Sadler
JE
Fujikawa
K
Amino acid sequence of human von Willebrand factor.
Biochemistry
25
1986
3171
54
Ruggeri
ZM
von Willebrand factor.
J Clin Invest
99
1997
559
55
Sakariassen
KS
Bolhuis
PA
Sixma
JJ
Human blood platelet adhesion to artery subendothelium is mediated by factor VIII-von Willebrand factor bound to subendothelium.
Nature
279
1979
636
56
Peterson
DM
Stathopoulos
NA
Giorgio
TD
Hellums
JD
Moake
JL
Shear-induced platelet aggregation requires von Willebrand factor and platelet membrane glycoproteins Ib and IIb-IIIa.
Blood
69
1987
625
57
Siediecki
CA
Lestini
BJ
Kottke-Marchant
KK
Eppell
SJ
Wilson
DL
Marchant
RE
Shear-dependent changes in the three-dimensional structure of human von Willebrand factor.
Blood
88
1996
2939
58
Russell
SD
Roth
GJ
Pseudo-von Willebrand disease: A mutation in the platelet glycoprotein Ibα gene associated with a hyperactive surface receptor.
Blood
81
1993
1787
59
Miller
JL
Cunningham
D
Lyle
VA
Finch
CN
Mutation in the gene encoding the α chain of platelet glycoprotein Ib in platelet-type von Willebrand disease.
Proc Natl Acad Sci USA
88
1991
4761
60
Miller
JL
Castella
A
Platelet-type von Willebrand's disease: Characterization of a new bleeding disorder.
Blood
60
1982
790
61
Weiss
HJ
Meyer
D
Rabinowitz
R
Pietu
G
Girma
J-P
Vicic
WJ
Rogers
J
Pseudo-von Willebrand's disease. An intrinsic platelet defect with aggregation by unmodified human factor VIII/von Willebrand factor and enhanced adsorption of its high-molecular-weight multimers.
N Engl J Med
306
1982
326
62
Ginsburg
D
Sadler
JE
Von Willebrand disease: A database of point mutations, insertions, and deletions. For the Consortium on von Willebrand Factor Mutations and Polymorphisms, and the Subcommittee on von Willebrand Factor of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis.
Thromb Haemost
69
1993
177
63
Andrews
RK
López
JA
Berndt
MC
Molecular mechanisms of platelet adhesion and activation.
Int J Biochem Cell Biol
29
1997
91
64
Mohri
H
Fujimura
Y
Shima
M
Yoshioka
A
Houghten
RA
Ruggeri
ZM
Zimmerman
T
Structure of the von Willebrand factor domain interacting with glycoprotein Ib.
J Biol Chem
263
1988
17901
65
Girma
JP
Takahashi
Y
Yoshioka
A
Diaz
J
Meyer
D
Ristocetin and botrocetin involve two distinct domains of von Willebrand factor for binding to platelet membrane glycoprotein Ib.
Thromb Haemost
64
1990
326
66
Berndt
MC
Ward
CM
Booth
WJ
Castaldi
PA
Mazurov
AV
Andrews
RK
Identification of aspartic acid 514 through glutamic acid 542 as a glycoprotein Ib-IX complex receptor recognition sequence in von Willebrand factor. Mechanism of modulation of von Willebrand factor by ristocetin and botrocetin.
Biochemistry
31
1992
11144
67
Sugimoto
M
Mohri
H
McClintock
RA
Ruggeri
ZM
Identification of discontinuous von Willebrand factor sequences involved in complex formation with botrocetin. A model for the regulation of von Willebrand factor binding to platelet glycoprotein Ib.
J Biol Chem
266
1991
18172
68
Matsushita
T
Sadler
JE
Identification of amino acid residues essential for von Willebrand factor binding to platelet glycoprotein Ib. Charged-to-alanine scanning mutagenesis of the A1 domain of human von Willebrand factor.
J Biol Chem
270
1995
13406
69
Vicente
V
Kostel
PJ
Ruggeri
ZM
Isolation and functional characterization of the von Willebrand factor-binding domain located between residues His1-Arg293 of the α-chain of glycoprotein Ib.
J Biol Chem
263
1988
18473
70
Andrews
RK
Booth
WJ
Gorman
JJ
Castaldi
PA
Berndt
MC
Purification of botrocetin from Bothrops jararaca venom. Analysis of the botrocetin-mediated interaction between von Willebrand factor and the human platelet membrane glycoprotein Ib-IX complex.
Biochemistry
28
1989
8317
71
Murata
M
Ware
J
Ruggeri
ZM
Site-directed mutagenesis of a soluble recombinant fragment of platelet glycoprotein Ibα demonstrating negatively charged residues involved in von Willebrand factor binding.
J Biol Chem
266
1991
15474
72
Marchese
P
Murata
M
Mazzucato
M
Pradella
P
De Marco
L
Ware
J
Ruggeri
ZM
Identification of three tyrosine residues of glycoprotein Ibα with distinct roles in von Willebrand factor and α-thrombin binding.
J Biol Chem
270
1995
9571
73
Cruz
MA
Petersen
E
Turci
SM
Handin
RI
Functional analysis of a recombinant glycoprotein Ibα polypeptide which inhibits von Willebrand factor binding to the platelet glycoprotein Ib-IX complex and to collagen.
J Biol Chem
267
1992
1303
74
Hess
D
Schaller
J
Rickli
EE
Clemetson
KJ
Identification of the disulphide bonds in human platelet glycocalicin.
Eur J Biochem
199
1991
389
75
Miller
JL
Lyle
VA
Cunningham
D
Mutation of leucine-57 to phenylalanine in a platelet glycoprotein Ibα leucine tandem repeat occurring in patients with an autosomal dominant variant of Bernard-Soulier disease.
Blood
79
1992
439
76
Ware
J
Russell
SR
Marchese
P
Murata
M
Mazzucato
M
De Marco
L
Ruggeri
ZM
Point mutation in a leucine-rich repeat of platelet glycoprotein Ibα resulting in the Bernard-Soulier syndrome.
J Clin Invest
92
1993
1213
77
Savage
B
Saldivar
E
Ruggeri
ZM
Initiation of platelet adhesion by arrest onto fibrinogen or translocation on von Willebrand factor.
Cell
84
1996
289
78
Moroi
M
Jung
SM
Nomura
S
Sekiguchi
S
Ordinas
A
Diaz-Ricart
M
Analysis of the involvement of the von Willebrand factor-glycoprotein Ib interaction in platelet adhesion to a collagen-coated surface under flow conditions.
Blood
90
1997
4413
79
De Marco
L
Mazzucato
M
Masotti
A
Ruggeri
ZM
Localization and characterization of an α-thrombin-binding site on platelet glycoprotein Ibα.
J Biol Chem
269
1994
6478
80
Katagiri
Y
Hayashi
Y
Yamamoto
K
Tanoue
K
Kosaki
G
Yamazaki
H
Localization of von Willebrand factor and thrombin-interactive domains on human platelet glycoprotein Ib.
Thromb Haemost
63
1990
122
81
Gralnick
HR
Williams
S
McKeown
LP
Hansmann
K
Fenton
JW
Krutzsch
H
High-affinity α-thrombin binding to platelet glycoprotein Ibα: Identification of two binding domains.
Proc Natl Acad Sci USA
91
1994
6334
82
Dong
J-F
Sae-Tung
G
López
JA
Role of glycoprotein V in the formation of the platelet high affinity thrombin-binding site.
Blood
89
1997
4355
83
Vu
TH
Hung
DT
Wheaton
VI
Coughlin
SR
Molecular cloning of a functional thrombin receptor reveals a novel proteolytic mechanism of receptor activation.
Cell
64
1991
1057
84
Ishihara
H
Connolly
AJ
Zeng
D
Kahn
ML
Zheng
YW
Timmons
C
Tram
T
Coughlin
SR
Protease-activated receptor 3 is a second thrombin receptor in humans.
Nature
386
1997
502
85
Jamieson
GA
Okumura
T
Reduced thrombin binding and aggregation in Bernard-Soulier platelets.
J Clin Invest
61
1978
861
86
Berndt
MC
Gregory
C
Dowden
G
Castaldi
PA
Thrombin interactions with platelet membrane proteins.
Ann NY Acad Sci
485
1986
374
87
Greco
NJ
Tandon
NN
Jones
GD
Kornhauser
R
Jackson
B
Yamamoto
N
Tanoue
K
Jamieson
GA
Contribution of glycoprotein Ib and the seven transmembrane domain receptor to increases in platelet cytoplasmic [Ca2+] induced by α-thrombin.
Biochemistry
35
1996
906
88
Jamieson
GA
Pathophysiology of platelet thrombin receptors.
Thromb Haemost
78
1997
242
89
Shattil
SJ
Ginsberg
MH
Brugge
JS
Adhesive signaling in platelets.
Curr Opin Cell Biol
6
1994
695
90
Du
X
Ginsberg
MH
Integrin αIIbβ3 and platelet function.
Thromb Haemost
78
1997
96
91
Andrews
RK
Kroll
MH
Ward
CM
Rose
JW
Scarborough
RM
Smith
AI
López
JA
Berndt
MC
Binding of a novel 50-kDa alboaggregin from Trimeresurus albolabris and related viper venom proteins to the platelet membrane glycoprotein Ib-IX-V complex. Effect on platelet aggregation and glycoprotein Ib-mediated platelet activation.
Biochemistry
35
1996
12629
92
Kroll
MH
Harris
TS
Moake
JL
Handin
RI
Schafer
AI
von Willebrand factor binding to platelet GpIb initiates signals for platelet activation.
J Clin Invest
88
1991
1568
93
Ikeda
Y
Handa
M
Kamata
T
Kawano
K
Kawai
Y
Watanabe
K
Kawakami
K
Sakai
K
Fukuyama
M
Itagaki
I
Yoshioka
A
Ruggeri
ZM
Transmembrane calcium influx associated with von Willebrand factor binding to GP Ib in the initiation of shear-induced platelet aggregation.
Thromb Haemost
69
1993
496
94
Jackson
SP
Schoenwaelder
SM
Yuan
Y
Rabinowitz
I
Salem
HH
Mitchell
CA
Adhesion receptor activation of phosphatidylinositol 3-kinase. von Willebrand factor stimulates the cytoskeletal association and activation of phosphatidylinositol 3-kinase and pp60c-src in human platelets.
J Biol Chem
269
1994
27093
95
Razdan
K
Hellums
JD
Kroll
MH
Shear-stress-induced von Willebrand factor binding to platelets causes the activation of tyrosine kinase(s).
Biochem J
302
1994
681
96
Andrews
RK
Fox
JE
Identification of a region in the cytoplasmic domain of the platelet membrane glycoprotein Ib-IX complex that binds to purified actin-binding protein.
J Biol Chem
267
1992
18605
97
Fox
JE
Boyles
JK
Berndt
MC
Steffen
PK
Anderson
LK
Identification of a membrane skeleton in platelets.
J Cell Biol
106
1988
1525
98
Hartwig
JH
DeSisto
M
The cytoskeleton of the resting human blood platelet: Structure of the membrane skeleton and its attachment to actin filaments.
J Cell Biol
112
1991
407
99
Fox
JEB
Lipfer
L
Clark
EA
Reynolds
CC
Austin
CD
Brugge
JS
On the role of the platelet membrane skeleton in mediating signal transduction.
J Biol Chem
268
1993
25973
100
(suppl 4)
Fox
JE
Platelet activation: New aspects.
Haemostasis
26
1996
102
101
Fox
JE
The platelet cytoskeleton.
Thromb Haemost
70
1993
884
102
Dong
J-F
Li
CQ
Sae-Tung
G
Hyun
W
Afshar-Kharghan
V
López
JA
The cytoplasmic domain of glycoprotein(GP) Ibα constrains the lateral diffusion of the GP Ib-IX complex and modulates von Willebrand factor binding.
Biochemistry
36
1997
12421
103
Du
X
Harris
SJ
Tetaz
TJ
Ginsberg
MH
Berndt
MC
Association of a phospholipase A2 (14-3-3 protein) with the platelet glycoprotein Ib-IX complex.
J Biol Chem
269
1994
18287
104
Du
X
Fox
JE
Pei
S
Identification of a binding sequence for the 14-3-3 protein within the cytoplasmic domain of the adhesion receptor, platelet glycoprotein Ibα.
J Biol Chem
271
1996
7362
105
Zupan
LA
Steffens
DL
Berry
CA
Landt
M
Gross
RW
Cloning and expression of a human 14-3-3 protein mediating phospholipolysis. Identification of an arachidonoyl-enzyme intermediate during catalysis.
J Biol Chem
267
1992
8707
106
Robinson
K
Jones
D
Patel
Y
Martin
H
Madrazo
J
Martin
S
Howell
S
Elmore
M
Finnen
MJ
Aitken
A
Mechanism of inhibition of protein kinase C by 14-3-3 isoforms. 14-3-3 isoforms do not have phospholipase A2 activity.
Biochem J
299
1994
853
107
Aitken
A
14-3-3 and its possible role in co-ordinating multiple signalling pathways.
Trends Cell Biol
6
1996
341
108
Muslin
AJ
Tanner
JW
Allen
PM
Shaw
AS
Interaction of 14-3-3 with signaling proteins is mediated by the recognition of phosphoserine.
Cell
84
1996
889
109
Zha
J
Harada
H
Yang
E
Jockel
J
Korsmeyer
SJ
Serine phosphorylation of death agonist BAD in response to survival factor results in binding to 14-3-3 not BCL-X(L).
Cell
87
1996
619
110
Andrews
RK
Harris
SJ
McNally
T
Berndt
MC
Binding of purified 14-3-3ζ signaling protein to discrete amino acid sequences within the cytoplasmic domain of the platelet membrane glycoprotein Ib-IX-V complex.
Biochemistry
37
1998
638
111
López
JA
Leung
B
Reynolds
CC
Li
CQ
Fox
JE
Efficient plasma membrane expression of a functional platelet glycoprotein Ib-IX complex requires the presence of its three subunits.
J Biol Chem
267
1992
12851
112
López
JA
Weisman
S
Sanan
DA
Sih
T
Chambers
M
Li
CQ
Glycoprotein (GP) Ibβ is the critical subunit linking GP Ibα and GP IX in the GP Ib-IX complex. Analysis of partial complexes.
J Biol Chem
269
1994
23716
113
López
JA
Li
CQ
Weisman
S
Chambers
M
The GP Ib-IX “complex-specific” monoclonal antibody SZ1 binds to a conformation-sensitive epitope on GP IX: Implications for the target antigen of quinine/quinidine-dependent autoantibodies.
Blood
85
1995
1254
114
Wright
SD
Michaelides
K
Johnson
DJ
West
NC
Tuddenham
EG
Double heterozygosity for mutations in the platelet glycoprotein IX gene in three siblings with Bernard-Soulier syndrome.
Blood
81
1993
2339
115
Ludlow
LB
Schick
BP
Budarf
ML
Driscoll
DA
Zackai
EH
Cohen
A
Konkle
BA
Identification of a mutation in a GATA binding site of the platelet glycoprotein Ibβ promoter resulting in the Bernard-Soulier syndrome.
J Biol Chem
271
1996
22076
116
Noda
M
Fujimura
K
Takafuta
T
Shimomura
T
Fujimoto
T
Yamamoto
N
Tanoue
K
Arai
M
Suehiro
A
Kakishita
E
Shimasaki
A
Kuramoto
A
Heterogenous expression of glycoprotein Ib, IX and V in platelets from two patients with Bernard-Soulier syndrome caused by different genetic abnormalities.
Thromb Haemost
74
1995
1411
117
Meyer
S
Kresbach
G
Häring
P
Schumpp-Vonach
B
Clemetson
KJ
Hadváry
P
Steiner
B
Expression and characterization of functionally active fragments of the platelet glycoprotein (GP) Ib-IX complex in mammalian cells. Incorporation of GP Ibα into the cell surface membrane.
J Biol Chem
268
1993
20555
118
Calverley
DC
Yagi
M
Stray
SM
Roth
GJ
Human platelet glycoprotein V: Its role in enhancing expression of the glycoprotein Ib receptor.
Blood
86
1995
1361
119
Meyer
SC
Fox
JE
Interaction of platelet glycoprotein V with glycoprotein Ib-IX regulates expression of the glycoprotein and binding of von Willebrand factor to glycoprotein Ib-IX in transfected cells.
J Biol Chem
270
1995
14693
120
Afshar-Kharghan
V
López
JA
Bernard-Soulier syndrome caused by a dinucleotide deletion and reading frameshift in the region encoding the glycoprotein Ibα transmembrane domain.
Blood
90
1997
2634
121
Noda
M
Fujimura
K
Takafuta
T
Shimomura
T
Fujii
T
Katsutani
S
Fujimoto
T
Kuramoto
A
Yamazaki
T
Mochizuki
T
Matsuzaki
M
Sano
M
A point mutation in glycoprotein IX coding sequence (Cys73(TGT) to Tyr(TAT)) causes impaired surface expression of GP Ib-IX-V complex in two families with Bernard-Soulier syndrome.
Thromb Haemost
6
1996
874
122
Holmberg
L
Karpman
D
Nilsson
I
Olofsson
T
Bernard-Soulier syndrome Karlstad: Trp 498→Stop mutation resulting in a truncated glycoprotein Ibα that contains part of the transmembrane domain.
Br J Haematol
98
1997
57
123
Wu
G
Meloni
FJ
Shapiro
SS
Platelet glycoprotein (Gp) IX associates with Gp Ibα in the platelet membrane GpIb complex.
Blood
87
1996
2782
124
(abstr, suppl 1)
Dong
J-F
López
JA
Complex formation and intracellular transport of the polypeptides of the platelet glycoprotein Ib-IX-V complex.
Blood
88
1996
624a
125
Wenger
RH
Kieffer
N
Wicki
AN
Clemetson
KJ
Structure of the human blood platelet membrane glycoprotein Ibα gene.
Biochem Biophys Res Commun
156
1988
389
126
Hickey
MJ
Roth
GJ
Characterization of the gene encoding human platelet glycoprotein IX.
J Biol Chem
268
1993
3438
127
Mikol
DD
Alexakos
MJ
Bayley
CA
Lemons
RS
Le Beau
MM
Stefansson
K
Structure and chromosomal localization of the gene for the oligodendrocyte-myelin glycoprotein.
J Cell Biol
111
1990
2673
128
Sprandio
JD
Shapiro
SS
Thiagarajan
P
McCord
S
Cultured human umbilical vein endothelial cells contain a membrane glycoprotein immunologically related to platelet glycoprotein Ib.
Blood
71
1988
234
129
Asch
AS
Adelman
B
Fujimoto
M
Nachman
RL
Identification and isolation of a platelet GPIb-like protein in human umbilical vein endothelial cells and bovine aortic smooth muscle cells.
J Clin Invest
81
1988
1600
130
Konkle
BA
Shapiro
SS
Asch
AS
Nachman
RL
Cytokine-enhanced expression of glycoprotein Ibα in human endothelium.
J Biol Chem
265
1990
19833
131
Rajagopalan
V
Essex
DW
Shapiro
SS
Konkle
BA
Tumor necrosis factor-α modulation of glycoprotein Ibα expression in human endothelial and erythroleukemia cells.
Blood
80
1992
153
132
Zieger
B
Hashimoto
Y
Ware
J
Alternative expression of platelet glycoprotein Ibβ mRNA from an adjacent 5′ gene with an imperfect polyadenylation signal sequence.
J Clin Invest
99
1997
520
133
Beacham
DA
Cruz
MA
Handin
RI
Glycoprotein Ib can mediate endothelial cell attachment to a von Willebrand factor substratum.
Thromb Haemost
73
1995
309
134
Bombeli
T
Schwartz
BR
Harlan
JM
Adhesion of activated platelets to endothelial cells: Evidence for a GPIIbIIIa-dependent bridging mechanism and novel roles for endothelial intercellular adhesion molecule 1 (ICAM-1), αvβ3 integrin, and GPIbα.
J Exp Med
187
1998
329
135
Perrault
C
Lankhof
H
Pidard
D
Kerbiriou-Nabias
D
Sixma
JJ
Meyer
D
Baruch
D
Relative importance of the glycoprotein Ib-binding domain and the RGD sequence of von Willebrand factor for its interaction with endothelial cells.
Blood
90
1997
2335
136
Uzan
G
Prenant
M
Prandini
M-H
Martin
F
Marguerie
G
Tissue-specific expression of the platelet GPIIb gene.
J Biol Chem
266
1991
8932
137
Prandini
M-H
Uzan
G
Martin
F
Thevenon
D
Marguerie
G
Characterization of a specific erythromegakaryocytic enhancer within the glycoprotein IIb promoter.
J Biol Chem
267
1992
10370
138
Lemarchandel
V
Ghysdael
J
Mignotte
V
Rahuel
C
Roméo
P-H
GATA and Ets cis-acting sequences mediate megakaryocyte-specific expression.
Mol Cell Biol
13
1993
668
139
Martin
F
Prandini
M-H
Thevenon
D
Marguerie
G
Uzan
G
The transcription factor GATA-1 regulates the promoter activity of the platelet glycoprotein IIb gene.
J Biol Chem
268
1993
21606
140
Block
KL
Poncz
M
Platelet glycoprotein IIb gene expression as a model of megakaryocyte-specific expression.
Stem Cells
13
1995
135
141
Hashimoto
Y
Ware
J
Identification of essential GATA and Ets binding motifs within the promoter of the platelet glycoprotein Ibα gene.
J Biol Chem
270
1995
24532
142
Bastian
LS
Yagi
M
Chan
C
Roth
GJ
Analysis of the megakaryocyte glycoprotein IX promoter identifies positive and negative regulatory domains and functional GATA and Ets sites.
J Biol Chem
271
1996
18554
143
Tsang
AP
Visvader
JE
Turner
CA
Fujiwara
Y
Yu
C
Weiss
MJ
Crossley
M
Orkin
SH
FOG, a multiple zinc finger protein, acts as a cofactor for transcription factor GATA-1 in erythroid and megakaryocytic differentiation.
Cell
90
1997
109
144
Krause
DS
Perkins
AS
Gotta find GATA a friend.
Nat Med
3
1997
960
145
Moroi
M
Jung
SM
Yoshida
N
Genetic polymorphism of platelet glycoprotein Ib.
Blood
64
1984
622
146
Meyer
M
Schellenberg
I
Platelet membrane glycoprotein Ib: Genetic polymorphism detected in the intact molecule and in proteolytic fragments.
Thromb Res
58
1990
233
147
Murata
M
Furihata
K
Ishida
F
Russell
SR
Ware
J
Ruggeri
ZM
Genetic and structural characterization of an amino acid dimorphism in glycoprotein Ibα involved in platelet transfusion refractoriness.
Blood
79
1992
3086
148
Kuijpers
RW
Faber
NM
Cuypers
HT
Ouwehand
WH
von dem Borne
AE
NH2-terminal globular domain of human platelet glycoprotein Ibα has a methionine145/threonine145 amino acid polymorphism, which is associated with the HPA-2 (Ko) alloantigens.
J Clin Invest
89
1992
381
149
Simsek
S
Bleeker
PM
van der Schoot
CE
von dem Borne
AE
Association of variable number of tandem repeats (VNTR) in glycoprotein Ibα and HPA-2 alloantigens.
Thromb Haemost
72
1994
757
150
Ishida
F
Saji
H
Maruya
E
Furihata
K
Human platelet-specific antigen, Siba, is associated with the molecular weight polymorphism of glycoprotein Ibα.
Blood
78
1991
1722
151
Kaski
S
Kekomaki
R
Partanen
J
Systematic screening for genetic polymorphism in human platelet glycoprotein Ibα.
Immunogenetics
44
1996
170
152
Suzuki
K
Hayashi
T
Akiba
J
Yahagi
A
Tajima
K
Satoh
S
Sasaki
H
Sty I polymorphism at nucleotide 1610 in the human platelet glycoprotein Ib alpha gene.
Jpn J Human Genet
41
1996
419
153
Lindsay
EA
Shaffer
LG
Carrozzo
R
Greenberg
F
Baldini
A
De novo tandem duplication of chromosome segment 22q11-q12: Clinical, cytogenetic, and molecular characterization.
Am J Med Genet
56
1995
296
154
Buetow
KH
Duggan
D
Yang
B
Ludwigsen
S
Puck
J
Porter
J
Budarf
M
Spielman
R
Emanuel
BS
A microsatellite-based multipoint index map of human chromosome 22.
Genomics
18
1993
329
155
Fibison
WJ
Budarf
M
McDermid
H
Greenberg
F
Emanuel
BS
Molecular studies of DiGeorge syndrome.
Am J Hum Genet
46
1990
888
156
MacCollin
M
Romano
D
Budarf
M
Denny
C
Trofatter
J
Menon
A
Rouleau
G
Fontaine
B
Emanuel
B
Gusella
J
A set of STS assays targeting the chromosome 22 physical framework markers.
Genomics
15
1993
680
157
Berndt
MC
Congenital disorders of platelet function
Loscalzo
J
Schafer
AI
Thrombosis and Hemorrhage.
1994
615
Blackwell Scientific
Boston, MA
158
Grové
SS
Kromberg
JGR
Bernard-Soulier syndrome in two Afrikaner families.
S Afr Med J
67
1985
1050
159
Mant
MJ
DDAVP in Bernard-Soulier syndrome.
Thromb Res
52
1988
77
160
Caen
JP
Nurden
AT
Jeanneau
C
Michel
H
Tobelem
G
Levy-Toledano
S
Sultan
Y
Valensi
F
Bernard
J
Bernard-Soulier syndrome: A new platelet glycoprotein abnormality. Its relationship with platelet adhesion to subendothelium and with the factor VIII von Willebrand protein.
J Lab Clin Med
87
1976
586
161
Peaceman
AM
Katz
AR
Laville
M
Bernard-Soulier syndrome complicating pregnancy: A case report.
Obstet Gynecol
73
1989
457
162
Michalas
S
Malamitsi-Puchner
A
Tsevrenis
H
Pregnancy and delivery in Bernard-Soulier syndrome.
Acta Obstet Gynecol Scand
63
1984
185
163
Heslop
HE
Hickton
CM
Laird
E
Tait
JD
Doig
JR
Beard
EJ
Twin pregnancy and parturition in a patient with the Bernard Soulier syndrome.
Scand J Haematol
37
1986
71
164
Saade
G
Homsi
R
Seoud
M
Bernard-Soulier syndrome in pregnancy; a report of four pregnancies in one patient, and review of the literature.
Eur J Obstet Gynecol Reprod Biol
40
1991
149
165
Peng
TC
Kickler
TS
Bell
WR
Haller
E
Obstetric complications in a patient with Bernard-Soulier syndrome.
Am J Obstet Gynecol
165
1991
425
166
Avila
MA
Jacyntho
C
Santos
ML
Murta
C
Hoirich
S
Chalon
I
Resende
O
Syndrome de Bernard-Soulier et grossesse: Un cas.
J Gynecol Obstet Biol Reprod
21
1992
73
167
de Moerloose
P
Vogel
JJ
Clemetson
KJ
Petite
J
Bienz
D
Bouvier
CA
Syndrome de Bernard-Soulier dans une famille suisse.
Schweiz Med Wochenschr
117
1987
1817
168
Cuthbert
RJG
Watson
HHK
Handa
SI
Abbott
I
Ludlam
CA
DDAVP shortens the bleeding time in Bernard-Soulier syndrome.
Thromb Res
49
1988
649
169
Bunescu
A
Lindahl
T
Solum
NO
Schulman
S
Larsson
A
Lundahl
J
Egberg
N
Partial expression of GPIb measured by flow cytometry in two patients with Bernard-Soulier syndrome.
Thromb Res
76
1994
441
170
Li
C
Pasquale
DN
Roth
GJ
Bernard-Soulier syndrome with severe bleeding: Absent platelet glycoprotein Ib alpha due to a homozygous one-base deletion.
Thromb Haemost
76
1996
670
171
Waldenström
E
Holmberg
L
Axelsson
U
Winqvist
I
Nilsson
IM
Bernard-Soulier syndrome in two Swedish families: Effect of DDAVP on bleeding time.
Eur J Haematol
46
1991
182
172
Simsek
S
Admiraal
LG
Modderman
PW
van der Schoot
CE
von dem Borne
AEGK
Identification of a homozygous single base pair deletion in the gene coding for the human platelet glycoprotein Ibα causing Bernard-Soulier syndrome.
Thromb Haemost
72
1994
444
173
Nomura
K
Harioka
T
Itoh
T
Kitajima
T
Uno
K
Kagawa
D
Sone
T
Anesthetic management of a patient with Bernard-Soulier syndrome.
Masui
42
1993
1521
174
Kemahli
S
Canatan
D
Uysal
Z
Akar
N
Cin
S
Arcasoy
A
DDAVP shortens bleeding time in Bernard-Soulier syndrome.
Thromb Haemost
71
1994
675
175
De Marco
L
Mazzucato
M
Fabris
F
De Roia
D
Coser
P
Girolami
A
Vicente
V
Ruggeri
ZM
Variant Bernard-Soulier syndrome type Bolzano. A congenital bleeding disorder due to a structural and functional abnormality of the platelet glycoprotein Ib-IX complex.
J Clin Invest
86
1990
25
176
Kenny
D
Newman
PJ
Morateck
PA
Montgomery
RR
A dinucleotide deletion results in defective membrane anchoring and circulating soluble glycoprotein Ibα in a novel form of Bernard-Soulier syndrome.
Blood
90
1997
2626
177
(abstr)
Kaski
S
Partanen
J
Salmi
TT
Kekomäki
R
Different molecular origin of Bernard-Soulier syndrome (BSS) reflected in varying expression of platelet glycoprotein (GP) Ib/IX/V complex.
Thromb Haemost
77
1997
68
178
Takahashi
H
Murata
M
Moriki
T
Anbo
H
Furukawa
T
Nikkuni
K
Shibata
A
Handa
M
Kawai
Y
Watanabe
K
Ikeda
Y
Substitution of Val for Met at residue 239 of platelet glycoprotein Ibα in Japanese patients with platelet-type von Willebrand disease.
Blood
85
1995
727
179
Kunishima
S
Heaton
DC
Naoe
T
Hickton
C
Mizuno
S
Saito
H
Kamiya
T
De novo mutation of the platelet glycoprotein Ibα gene in a patient with pseudo-von Willebrand disease.
Blood Coagul Fibrinolysis
8
1997
311
180
Pincus
MR
Dykes
DC
Carty
RP
Miller
JL
Conformational energy analysis of the substitution of Val for Gly 233 in a functional region of platelet GPIbα in platelet-type von Willebrand disease.
Biochim Biophys Acta
1097
1991
133
181
Pincus
MR
Carty
RP
Miller
JL
Structural implications of the substitution of Val for Met at residue 239 in the alpha chain of human platelet glycoprotein IB.
J Prot Chem
13
1994
629
182
Budarf
ML
Konkle
BA
Ludlow
LB
Michaud
D
Li
M
Yamashiro
DJ
McDonald
D
Zackai
EH
Driscoll
DA
Identification of a patient with Bernard-Soulier syndrome and a deletion in the DiGeorge/Velo-cardio-facial chromosomal region in 22q11.2.
Hum Mol Genet
4
1995
763
183
Kunishima
S
Lopez
JA
Kobayashi
S
Imai
N
Kamiya
T
Saito
H
Naoe
T
Missense mutations of the glycoprotein (GP) Ibβ gene impairing the GPIb α/β disulfide linkage in a family with giant platelet disorder.
Blood
89
1997
2404
184
Sae-Tung
G
Dong
J
López
JA
Biosynthetic defect in platelet glycoprotein IX mutants associated with Bernard-Soulier syndrome.
Blood
87
1996
1361
185
Berndt
MC
Kabral
A
Grimsley
P
Watson
N
Robertson
TI
Bradstock
KF
An acquired Bernard-Soulier-like platelet defect associated with juvenile myelodysplastic syndrome.
Br J Haematol
68
1988
97
186
Hiçsönmez
G
Gümrük
F
Çetin
M
Özbek
N
Tüncer
M
Gürsel
T
Bernard-Soulier-like functional platelet defect in myelodysplastic syndrome and in acute myeloblastic leukemia associated with trilineage myelodysplasia.
Turk J Pediatr
37
1995
425
187
Devine
DV
Currie
MS
Rosse
WF
Greenberg
CS
Pseudo-Bernard-Soulier syndrome: Thrombocytopenia caused by autoantibody to platelet glycoprotein Ib.
Blood
70
1987
428
188
Varon
D
Gitel
SN
Varon
N
Lahav
J
Dardik
R
Klepfish
A
Berrebi
A
Immune Bernard Soulier-like syndrome associated with anti-glycoprotein-IX antibody.
Am J Hematol
41
1992
67
189
Beales
ILP
An acquired-pseudo Bernard Soulier syndrome occuring with autoimmune chronic active hepatitis and anti-cardiolipin antibody.
Postgrad Med J
70
1994
305
190
White
JG
Burris
SM
Hasegawa
D
Johnson
M
Micropipette aspiration of human blood platelets: A defect in Bernard-Soulier's syndrome.
Blood
63
1984
1249
191
McNicol
A
Drouin
J
Clemetson
KJ
Gerrard
JM
Phospholipase C activity in platelets from Bernard-Soulier syndrome patients.
Arterioscler Thromb
13
1993
1567
192
Caen
JP
Bellucci
S
The defective prothrombin consumption in Bernard-Soulier syndrome. Hypotheses from 1948 to 1982.
Blood Cells
9
1983
389
193
Bockenstedt
PL
Laboratory methods in hemostasis
Loscalzo
J
Schafer
AI
Thrombosis and Hemorrhage.
1994
455
Blackwell Scientific
Boston, MA
194
Bradford
HN
Dela Cadena
RA
Kunapuli
SP
Dong
J-F
López
JA
Colman
RW
Human kininogens regulate thrombin binding to platelets through the glycoprotein Ib-IX-V complex.
Blood
90
1997
1508
195
(abstr)
Joseph
K
Bahou
W
Kaplan
AP
Evidence that the zinc-dependent platelet-binding protein of factor XII and high molecular weight kininogen is glycoprotein Ib.
J Invest Med
45
1997
267A
196
Coller
BS
Peerschke
EI
Lesley
E
Scudder
LE
Sullivan
CA
Studies with a murine monoclonal antibody that abolishes ristocetin-induced binding of von Willebrand factor to platelets: Additional evidence in support of GPIb as a platelet receptor for von Willebrand factor.
Blood
61
1983
99
197
Kunishima
S
Miura
H
Fukutani
H
Yoshida
H
Osumi
K
Kobayashi
S
Ohno
R
Naoe
T
Bernard-Soulier syndrome Kagoshima: Ser 444 → Stop mutation of glycoprotein (GP) Ibα resulting in circulating truncated GPIbα and surface expression of GPIbβ and GPIX.
Blood
84
1994
3356
198
Ware
J
Russell
SR
Vicente
V
Scharf
RE
Tomer
A
McMillan
R
Ruggeri
ZM
Nonsense mutation in the glycoprotein Ibα coding sequence associated with Bernard-Soulier syndrome.
Proc Natl Acad Sci USA
87
1990
2026
199
Simsek
S
Noris
P
Lozano
M
Pico
M
von dem Borne
AEGK
Ribera
A
Gallardo
D
Cys209Ser mutation in the platelet membrane glycoprotein Ibα gene is associated with Bernard Soulier syndrome.
Br J Haematol
88
1994
839
200
Li
C
Martin
S
Roth
G
The genetic defect in two well-studied cases of Bernard-Soulier syndrome: A point mutation in the fifth leucine-rich repeat of platelet glycoprotein Ibα.
Blood
86
1996
3805
201
Lipson
AH
Yuille
D
Angel
M
Thompson
PG
Vandervoord
JG
Beckenham
EJ
Velocardiofacial (Shprintzen) syndrome: An important syndrome for the dysmorphologist to recognise.
J Med Genet
28
1991
596
202
Ware
J
Hashimoto
Y
Zieger
B
Russell
S
Controlling elements of platelet glycoprotein Ibα expression.
C R Acad Sci III
319
1996
811
203
Rendu
F
Nurden
AT
Lebert
M
Caen
JP
Relationship between mepacrine-labelled dense body number, platelet capacity to accumulate 14C-5-HT and platelet density in the Bernard-Soulier and Hermansky-Pudlak syndromes.
Thromb Haemost
42
1979
694
204
McGregor
JL
Clemetson
KJ
James
E
Luscher
EF
Dechavanne
M
A comparison of the major platelet membrane glycoproteins from Bernard-Soulier syndrome with normals after radiolabelling of sialic acid or terminal galactose/N-acetylgalactosamine residues.
Thromb Res
17
1980
713
205
George
JN
Reimann
TA
Moake
JL
Morgan
RK
Cimo
PL
Sears
DA
Bernard-Soulier disease: A study of four patients and their parents.
Br J Haematol
48
1981
459
206
Drouin
J
McGregor
JL
Parmentier
S
Izaguirre
CA
Clemetson
KJ
Residual amounts of glycoprotein Ib concomitant with near-absence of glycoprotein IX in platelets of Bernard-Soulier patients.
Blood
72
1988
1086
207
McGill
M
Jamieson
GA
Drouin
J
Cho
MS
Rock
GA
Morphometric analysis of platelets in Bernard-Soulier syndrome: Size and configuration in patients and carriers.
Thromb Haemost
52
1984
37
208
De Marco
L
Fabris
F
Casonato
A
Fabris
P
Dal Ben
MG
Barbato
A
Girolami
A
Bernard-Soulier syndrome: diagnosis by an ELISA method using monoclonal antibodies in 2 new unrelated patients.
Acta Haematol
75
1986
203
209
Ingerslev
J
Stenbjerg
S
Taaning
E
A case of Bernard-Soulier syndrome: Study of platelet glycoprotein Ib in a kindred.
Eur J Haematol
39
1987
182
210
Nicholas
WL
Kaese
SE
Gastineau
DA
Otteman
LA
Bowie
EJW
Bernard-soulier syndrome: Whole blood diagnostic assays of platelets.
Mayo Clinic Proc
64
1989
522
211
Finch
CN
Miller
JL
Lyle
VA
Handin
RI
Evidence that an abnormality in the glycoprotein Ib alpha gene is not the cause of abnormal platelet function in a family with classic Bernard-Soulier disease.
Blood
75
1990
2357
212
Hourdillé
P
Pico
M
Jandrot-Perrus
M
Lacaze
D
Lozano
M
Nurden
AT
Studies on the megakaryocytes of a patient with the Bernard-Soulier syndrome.
Br J Haematol
76
1990
521
213
Poulsen
LO
Taaning
E
Variation in surface platelet glycoprotein Ib expression in Bernard-Soulier syndrome.
Haemostasis
20
1990
155
214
Clemetson
JM
Kyrle
PA
Brenner
B
Clemetson
KJ
Variant Bernard-Soulier syndrome associated with a homozygous mutation in the leucine-rich domain of glycoprotein IX.
Blood
84
1994
1124
215
Arai
M
Yamamoto
N
Akamatsu
N
Suzuki
H
Yamaguchi
A
Nishida
Y
Fukutake
K
Tanoue
K
Substantial expression of glycoproteins IX and V on the platelet surface from a patient with Bernard-Soulier syndrome.
Br J Haematol
87
1994
185
216
de La Salle
C
Baas
M-J
Lanza
F
Schwartz
A
Hanau
D
Chevalier
J
Gachet
C
Briquel
M
Cazenave
J-P
A three-base deletion removing a leucine residue in a leucine-rich repeat of platelet glycoprotein Ibα associated with a variant of Bernard-Soulier syndrome (Nancy I).
Br J Haematol
89
1995
386
217
Bellucci
S
Zini
JM
Bitoun
P
Dupuy
Y
Drouet
L
Tobelem
G
Caen
JP
Diffuse severe digestive angiodysplasia in Bernard-Soulier syndrome. Improvement of bleeding by oestroprogestative therapy.
Thromb Haemost
74
1995
1610
218
Kanaji
T
Okamura
T
Kuroiwa
M
Noda
M
Fujimura
K
Kuramoto
A
Sano
M
Nakano
S
Niho
Y
Molecular and genetic analysis of two patients with Bernard-Soulier syndrome: Identification of new mutations in glycoprotein Ibα gene.
Thromb Haemost
77
1997
1055
219
Noris
P
Simsek
S
Stibbe
J
von dem Borne
AEGK
A phenylalanine-55 to serine amino-acid substitution in the human glycoprotein IX leucine-rich repeat is associated with Bernard-Soulier syndrome.
Br J Haematol
97
1997
312